WO2022143179A1

WO2022143179A1 - Virtual character model creation method and apparatus, electronic device, and storage medium

Info

Publication number: WO2022143179A1
Application number: PCT/CN2021/138417
Authority: WO
Inventors: 林炳坤; 黄镇; 冯哲; 柴金祥
Original assignee: 魔珐(上海)信息科技有限公司; 上海墨舞科技有限公司
Priority date: 2020-12-31
Filing date: 2021-12-15
Publication date: 2022-07-07
Also published as: CN112712578B; CN112712578A

Abstract

The present disclosure relates to a virtual character model creation method and apparatus, an electronic device, and a storage medium. The method comprises: determining a character model to be created, said character model at least comprising a skin mesh; determining a template model according to said character model; determining a skeleton and a skinning weight of said character model according to a skin mesh, a skeleton, and a skinning weight of the template model; determining a modification of said character model according to a modification of the template model; and creating a character model according to the skin mesh, the skeleton, the skinning weight, and the modification of said character model. According to embodiments of the present disclosure, by selecting a preset template model, the skin mesh, the skeleton, the skinning weight, and the modification of the character model can be automatically created, thus having better interactivity, saving the labor cost and time cost that a technician creates a character model, and improving the efficiency of character model creation.

Description

Virtual character model creation method, apparatus, electronic device and storage medium

This application claims the priority of the Chinese patent application filed on December 31, 2020, with the application number of 202011626033.9 and the invention titled "Method, Apparatus, Electronic Device and Storage Medium for Creating Virtual Character Models", the entire contents of which are approved by Reference is incorporated in this application.

technical field

The present disclosure relates to the field of three-dimensional animation, and in particular, to a method, device, electronic device and storage medium for creating a virtual character model.

Background technique

With the development of computer graphics, 3D animation has received more and more attention in recent years due to its wide range of application scenarios, among which character animation is especially important in 3D animation.

Character rigging is a technique used in 3D animation and refers to the process of creating the bone structure of a character model. Driving the model through bone driving cannot express the effect of real-world biological bones driving muscle and skin, so in skeletal animation, it is necessary to modify the effect. Through digital skeleton movement and the modification of the skin surface, the character model can simulate the effect of the real world biological skeleton driving the muscle skin.

In the prior art, technicians need to manually bind and practice character models one by one, which is time-consuming and labor-intensive, affects the efficiency of creating character models, and indirectly causes low production capacity in the field of 3D animation.

SUMMARY OF THE INVENTION

In view of this, the present disclosure proposes a method, apparatus, electronic device and storage medium for creating a virtual character model.

According to an aspect of the present disclosure, there is provided a method for creating a virtual character model, the method comprising:

determining a character model to be created, the character model to be created at least includes a skin mesh;

According to the character model to be created, a template model is determined, and the template model includes a skin mesh, a bone matched with the skin mesh, a skin weight corresponding to the skin mesh, and each joint point. modification;

Determine the bones and skin weights of the character model to be created according to the skin meshes, bones, and skin weights of the template model;

According to the modification of the template model, determine the modification of the character model to be created;

A character model is created according to the skin mesh, bones, skin weights and modifications of the character model to be created.

In a possible implementation, the method further includes:

In the case that the topology of the skin mesh of the character model to be created is inconsistent with the topology of the skin mesh of the template model, determine that the topology of the skin mesh of the template model is that of the character model to be created. the topology of the skin mesh;

The shape of the skin mesh of the template model is modified according to the shape of the skin mesh of the character model to be created.

In a possible implementation manner, determining the bones and skin weights of the character model to be created according to the skin meshes, bones, and skin weights of the template model, including:

Determine the bone elongation ratio and the bone rotation angle of the bones of the character model to be created relative to the bones of the template model, and the vertices of the skin mesh of the character model to be created relative to the skin of the template model. Displacement compensation of the vertices of the mesh;

The bones of the character model to be created are determined according to the bone elongation ratio and the bone rotation angle and the bones of the template model.

In a possible implementation manner, determine the bone elongation ratio and the bone rotation angle of the bones of the character model to be created relative to the bones of the template model, and the skin mesh of the character model to be created. The displacement compensation of the vertices relative to the vertices of the skin mesh of the template model, including:

The joint point coordinates of the template model after bone stretching and rotation obtained according to the bone elongation ratio and the bone rotation angle are obtained according to the bone elongation ratio, the bone rotation angle, and the displacement compensation. The joint point coordinates obtained by weighting the skin mesh vertex coordinates around the joint points of the template model after the bone stretching and rotation are the same;

After the bones are stretched and rotated, the skin mesh vertex coordinates of the template model are the same as the skin mesh vertex coordinates of the character model to be created;

Wherein, after the bones are stretched and rotated, the coordinates of the skin mesh vertices of the template model are obtained according to the stretch ratio of the bones, the rotation angle of the bones and the displacement compensation.

In a possible implementation, it is characterized in that determining the bones of the character model to be created according to the bone elongation ratio and the bone rotation angle and the bones of the template model, including:

Determine the skeleton of the deformed template model according to the skeleton elongation ratio, the skeleton rotation angle and the skeleton of the template model;

modifying the skin mesh of the template model according to the displacement compensation and the skin weight of the template model;

When the degree of coincidence between the shape of the skin mesh of the modified template model and the shape of the skin mesh of the character model to be created is greater than a predetermined threshold, nest the bones of the deformed template model into the to-be-created character model. In the created character model, the bones of the character model to be created are determined.

In a possible implementation manner, determining the modification of the character model to be created according to the modification of the template model, including:

Determine the first side vector matrix corresponding to each grid unit in the skin grid of the character model to be created in the initial state, and each grid unit in the skin grid of the character model to be created after the joints are rotated The corresponding second edge vector matrix, the first edge vector matrix and the second edge vector matrix are determined according to the edge vector and the surface normal of the corresponding grid unit.

In a possible implementation manner, determine the first edge vector matrix corresponding to each grid unit in the skin mesh of the character model to be created in the initial state, and determine the character model to be created after the joints are rotated The second edge vector matrix corresponding to each grid cell in the skin grid of , including:

Make the flip transformation matrix of each grid unit in the skin grid of the character model to be created the same as the flip transformation matrix of each grid unit in the skin grid of the template model;

Wherein, the flip transformation matrix of each grid unit in the skin grid of the character model to be created is based on the first side vector matrix and the first edge vector matrix of each grid unit in the skin grid of the character model to be created. The second side vector matrix is obtained, and the flip transformation matrix of each grid unit in the skin grid of the template model is based on the first side vector matrix and the second side vector of each grid unit in the skin grid of the template model. matrix is obtained.

Make the flip transformation matrix of each grid unit in the skin grid of the character model to be created the same as the flip transformation matrix of the grid unit adjacent to the grid unit;

Wherein, the flip transformation matrix of the character model to be created is obtained according to the first edge vector matrix and the second edge vector matrix of each grid unit in the skin mesh of the character model to be created.

In a possible implementation manner, the skin weight of the character model to be created is determined according to the skin weight of the template model.

According to another aspect of the present disclosure, an apparatus for creating a virtual character model is provided, comprising:

a first character model determination module, configured to determine a character model to be created, where the character model to be created at least includes a skin mesh;

A template model determination module, configured to determine a template model according to the character model to be created, where the template model includes a skin mesh, a skeleton matching the skin mesh, and a skin corresponding to the skin mesh Weights and modifications corresponding to each joint point;

A second character model determination module, configured to determine the bones and skin weights of the character model to be created according to the skin meshes, bones, and skin weights of the template model;

a third role model determination module, configured to determine the modification of the to-be-created role model according to the modification of the template model;

The character model creation module is used for creating a character model according to the skin mesh, skeleton, skin weight and modification of the character model to be created.

In a possible implementation, the apparatus further includes:

A topology determination module, configured to determine that the topology of the skin mesh of the template model is the The topology of the skin mesh of the character model to be created;

A first skin mesh modification module, configured to modify the shape of the skin mesh of the template model according to the shape of the skin mesh of the character model to be created.

In a possible implementation manner, the second role model determination module includes:

The first determination submodule is used to determine the bone elongation ratio and the bone rotation angle of the bones of the character model to be created relative to the bones of the template model, and the vertices of the skin mesh of the character model to be created displacement compensation of the vertices of the skin mesh relative to the template model;

The second determination submodule is configured to determine the bones of the character model to be created according to the bone elongation ratio, the bone rotation angle and the bones of the template model.

In a possible implementation manner, the first determination submodule includes:

The first constraint sub-module is used to make the joint point coordinates of the template model after the bone stretching and rotation obtained according to the bone elongation ratio and the bone rotation angle, and the joint point coordinates of the bone rotation The angle and the joint point coordinates obtained by weighting the skin mesh vertex coordinates around the joint points of the template model after the bone stretching and rotation obtained by the displacement compensation are the same;

The second constraint submodule is used to make the skin mesh vertex coordinates of the template model after the bones are stretched and rotated to be the same as the skin mesh vertex coordinates of the character model to be created;

In a possible implementation manner, the second determination submodule includes:

a template model skeleton determination module, configured to determine the skeleton of the deformed template model according to the skeleton elongation ratio, the skeleton rotation angle and the skeleton of the template model;

A second skin mesh modification module, configured to modify the skin mesh of the template model according to the displacement compensation and the skin weight of the template model;

The character model skeleton determination module is used for determining the deformed template model when the shape of the skin mesh of the modified template model and the shape of the skin mesh of the to-be-created character model are more than a predetermined threshold. The bones of the to-be-created character model are nested, so as to determine the bones of the to-be-created character model.

In a possible implementation manner, the third role model determination module includes:

The third determination submodule is used to determine the first edge vector matrix corresponding to each grid unit in the skin mesh of the character model to be created in the initial state, and the character model to be created after the joints are rotated. The second side vector matrix corresponding to each grid unit in the skin grid, the first side vector matrix and the second side vector matrix are determined according to the side vector and the surface normal of the corresponding grid unit.

In a possible implementation manner, the third determination submodule includes:

The third constraint submodule is used to make the flip transformation matrix of each grid unit in the skin grid of the character model to be created the same as the flip transformation matrix of each grid unit in the skin grid of the template model;

The fourth constraint submodule is used to make the flip transformation matrix of each grid unit in the skin grid of the character model to be created identical with the flip transformation matrix of the grid unit adjacent to the grid unit;

In a possible implementation, the apparatus further includes:

The skin weight determination module is configured to determine the skin weight of the character model to be created according to the skin weight of the template model.

According to another aspect of the present disclosure, there is provided an electronic device for creating a virtual character model, including:

processor;

memory for storing processor-executable instructions;

Wherein, the processor is configured to implement the above method when executing the instructions.

According to another aspect of the present disclosure, there is provided a non-volatile computer-readable storage medium having computer program instructions stored thereon, wherein the computer program instructions implement the above method when executed by a processor.

By selecting the preset template model, the bones, skin weights and trimming of the character model can be automatically created, which has better interactivity, and at the same time saves the labor cost and time cost of the technicians in making the character model, and improves the production of the character model. s efficiency.

Other features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the accompanying drawings.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the disclosure, and together with the description, serve to explain the principles of the disclosure.

1 shows a flowchart of a method for creating a virtual character model according to an embodiment of the present disclosure;

2 shows a schematic diagram of an application scenario of a method for creating a virtual character model according to an embodiment of the present disclosure;

FIG. 3 shows a block diagram of an apparatus for creating a virtual character model according to an embodiment of the present disclosure.

FIG. 4 shows a block diagram of a virtual character model electronic device 800 according to an exemplary embodiment.

FIG. 5 shows a block diagram of an apparatus 1900 for creating a virtual character model according to an exemplary embodiment.

Detailed ways

Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numbers in the figures denote elements that have the same or similar functions. While various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

In addition, in order to better illustrate the present disclosure, numerous specific details are given in the following detailed description. It will be understood by those skilled in the art that the present disclosure may be practiced without certain specific details. In some instances, methods, means, components and circuits well known to those skilled in the art have not been described in detail so as not to obscure the subject matter of the present disclosure.

With the continuous development of computer graphics, 3D animation technology has a wide range of application scenarios because it can simulate the shape and action of real objects. In order to make the character model simulate the movements of real-world creatures, it needs to be bound and reshaped. However, in the related art, each character model needs to be bound and reshaped one by one, and the efficiency of producing 3D animation is low.

In order to improve the production efficiency of 3D animation, an embodiment of the present disclosure provides a method for creating a virtual character model, which corresponds to the skin mesh of the character model, the bones matched with the skin mesh, and the skin mesh corresponding to the relevant information of the template model. The skin weight and the modification corresponding to each joint point are automatically matched and generated, which has high production efficiency and application value.

The methods of the embodiments of the present disclosure can be invoked through an embedded plug-in in the animation production software, and a standard template (ie, a template model) for the animation production software to be invoked can be preset, and after the user selects the template, the implementation of the present disclosure can be started. Methods of Examples.

In a possible implementation manner, the virtual character creation method may be executed by an electronic device such as a terminal device or a server, and the terminal device may be a user equipment (User Equipment, UE), a mobile device, a user terminal, a terminal, a cellular phone, Cordless phones, personal digital assistants (Personal Digital Assistant, PDA), handheld devices, computing devices, vehicle-mounted devices, wearable devices, etc., the method can be implemented by the processor calling the computer-readable instructions stored in the memory. Alternatively, the method may be performed by a server.

FIG. 1 shows a flowchart of a method for creating a virtual character model according to an embodiment of the present disclosure. The method includes:

Step S101, determining a character model to be created, where the character model to be created at least includes a skin mesh;

Step S102: Determine a template model according to the character model to be created, where the template model includes a skin mesh, a bone matching the skin mesh, skin weights corresponding to the skin mesh, and various joints Click the corresponding modification;

Step S103, determining the bones and skin weights of the character model to be created according to the skin meshes, bones, and skin weights of the template model;

Step S104, determining the modification of the character model to be created according to the modification of the template model;

Step S105: Create a character model according to the skin mesh, skeleton, skin weight and modification of the character model to be created.

According to the embodiment of the present disclosure, by selecting a preset template model, the bones, skin weights and modifications of the character model can be automatically created, which has better interactivity and saves the labor cost and time cost of the technician for making the character model. , which improves the efficiency of making character models.

Among them, a plurality of template models with different heights, shorts, fats and thins and different genders can be preset, and the user can select a model similar to the character as the template model of the character model through the animation production software.

Among them, after determining the bones, skin weights, and shaping of the character model to be created, the user can make fine adjustments to them respectively to obtain a higher-quality character model.

where skin weights represent the coefficients by which skin mesh vertices are affected by bone motion.

In the process of creating the virtual character model, it is necessary to keep the topology of the template model and the character model to be created consistent for subsequent operations. In a possible implementation manner, when the topology of the skin mesh of the character model to be created is inconsistent with the topology of the skin mesh of the template model, determine the topology of the skin mesh of the template model is the topology of the skin mesh of the character model to be created; the shape of the skin mesh of the template model is modified according to the shape of the skin mesh of the character model to be created.

For example, you can adjust the topology by importing the template model, deform the skin mesh of the template model, and obtain that the shape of the skin mesh is consistent with that of the skin mesh of the character model, and the topology of the skin mesh is the same as that of the skin mesh of the template model. A new skin mesh with consistent topology, which is used as the skin mesh for the character model.

The shape of the skin mesh of the character model can be used as a reference for the deformation of the template model.

Due to the differences between the character model and the template model, the bones of the template model are adapted to the differences in body shape, height, limb length, etc. of the character model. It is necessary to rotate and stretch the bones of the template model to obtain the bones of the character model. Therefore, it is necessary to determine first. The three parameters are the bone elongation ratio of the bones of the character model relative to the bones of the template model, the rotation angle of the bones, and the displacement compensation of the vertices of the skin mesh of the character model relative to the vertices of the skin mesh of the template model.

In a possible implementation manner, in step S103, determining the bones and skin weights of the character model to be created according to the skin meshes, bones, and skin weights of the template model, including: determining the to-be-created character model The bone elongation ratio and the bone rotation angle of the bones of the created character model relative to the bones of the template model, and the vertices of the skin mesh of the character model to be created relative to the vertices of the skin mesh of the template model displacement compensation; determine the bones of the character model to be created according to the bone elongation ratio and the bone rotation angle and the bones of the template model.

Among them, the displacement compensation is to make the skin mesh of the template model after the deformation of the bones of the template model can fully have a closer shape to the skin mesh of the character model. For example, the arm muscles of the template model are not as strong as the arm muscles of the character model. Compensation makes the arm skin of the two more similar, similar to "watering" the skin of the template model's arm to make it fatter.

In a possible implementation manner, the joint point coordinates of the template model after bone stretching and rotation obtained according to the bone elongation ratio and the bone rotation angle are The rotation angle and the joint point coordinates obtained by weighting the skin mesh vertex coordinates around the joint points of the template model after the bone stretching and rotation obtained by the displacement compensation are the same; and the skin of the template model after the bone stretching and rotation is made. The mesh vertex coordinates are the same as the skin mesh vertex coordinates of the character model to be created.

Wherein, after the bones are stretched and rotated, the skin mesh vertex coordinates of the character are obtained according to the stretch ratio of the bones, the rotation angle of the bones and the displacement compensation.

Among them, the relative position between the coordinates of the joint points of the template model and the coordinates of the surrounding skin mesh vertices can be referred to as the relative position weight, and the relative position weight maintains the relationship between the joint points of the template model after bone deformation and the surrounding skin mesh. The relative position is consistent with the relative position between the bone points of the template model and the surrounding skin mesh before the bone deformation, wherein the relative position weight remains unchanged.

According to this embodiment, the joint point coordinates of the template model after bone stretching and rotation obtained according to the bone elongation ratio and the bone rotation angle are compared with those obtained according to the bone elongation ratio, the bone rotation angle, and The joint point coordinates obtained by weighting the skin mesh vertex coordinates around the joint points of the template model after the bone stretching and rotation obtained by the displacement compensation are the same; and the skin mesh vertex coordinates of the template model after the bone stretching and rotation are the same as The two constraints that the coordinates of the skin mesh vertexes of the character model to be created are the same to determine the bone elongation ratio and the bone rotation angle of the bones of the character model relative to the bones of the template model, and the skin mesh of the character model. The displacement of the vertices of the template model relative to the vertices of the skin mesh of the template model compensates these three parameters, so as to realize the automatic migration of template bones to character bones, save the labor cost and time cost of manual migration by technicians, and improve the production of character models. efficiency. Two constraints ensure that the bones can be correctly embedded in the skin mesh of the character model. The former ensures that the bones of the character model migrated from the template model are adapted to the skin mesh of the character model itself, and the latter ensures that the template The adaptation between the model and the character model makes the parameters of the obtained character model more accurate and the visual effect is better. At the same time, through automatic migration and minor repairs by technicians, the character model can be bound to the bone position more accurately.

In one example, the determination process is detailed with the following example:

The relative position relationship between the coordinates of the joint points of the template model and the coordinates of the surrounding skin mesh vertices can be expressed as: the coordinate J of the joint point k in the template model can pass the relative position weight a _i of the joint point k and the joint point k The coordinates v _i of the skin mesh vertices among the surrounding n skin mesh vertices are determined. Wherein, the value of a _i is less than 1, and a ₀ +a ₁ +... ₊ an =1.

Among them, through the known J and v _i of the template model, the relative position weight of the skin grid points of the template model can be determined by the optimization solution method.

The coordinates J of the joint points of the template model after bone stretching and rotation deformation can also be obtained by affine transformation using the following rotation, translation and scaling matrices:

Further, the affine transformation transformation matrix includes: M _father , T, RO, _ve , s, q, R(q). Among them, M _father represents the affine transformation matrix of the parent node of the joint point, T represents the translation transformation matrix from the parent node of the joint point to the joint point, RO represents the rotation transformation matrix of the bone orientation, _ve is the unit vector, and the above parameters can be obtained from the template Obtained from the model; s and q are unknown parameters, s represents the bone elongation ratio of the bones of the character model relative to the bones of the template model, q represents the bone rotation angle of the bones of the character model relative to the bones of the template model, R(q) Represents the joint point rotation transformation matrix.

In order to make the bones drive the skin mesh and make the skin mesh move with the bones, the linear skinning algorithm can be used to determine the mesh vertex coordinates v′ _i of the template model after the bones are stretched and rotated. The linear skinning algorithm can use the formula (1 )express:

Among them, RT(s,q) represents the rotation and translation transformation matrix of the joint point,

Represents the local coordinates of the mesh vertex, vo _i represents the displacement compensation of the skin mesh vertex of the character model relative to the skin mesh vertex of the template model, w _ij represents the linear skin weight, that is, the i-th skin mesh vertex is affected by the j-th skin mesh vertex. The coefficient of the influence of joint point motion, n represents the total number of joint points. Except for the parameters s, q and vo _i , other parameters can be determined by the template model.

There are two constraints between the character model and the template model, one is the joint point coordinates of the template model after the bone stretching and rotation obtained according to the bone elongation ratio and the bone rotation angle, and the other is the The joint point coordinates obtained by weighting the skin mesh vertex coordinates around the joint points of the template model after the bone stretching and rotation obtained by the length magnification, the bone rotation angle, and the displacement compensation are the same, which can be expressed by the following constraint equations :

Among them, a _ij represents the relative position weight between the j-th joint point of the template model and the i-th skin mesh vertex around it, that is, the relative position weight a _i of the j-th joint point. J _j represents the coordinate of the j-th joint point of the template model after bone deformation. Among them, J _j can be obtained by affine transformation. v′ _i is the vertex coordinates of the skin mesh of the template model deformed by the bones, which can be obtained by formula (1).

The second constraint condition is that the skin mesh vertex coordinates of the template model are the same as the skin mesh vertex coordinates of the character model to be created after the bones are stretched and rotated, which can be expressed by the following constraint equation:

in,

The coordinates representing the ith skin mesh vertex of the skin mesh of the character model can be derived from the original data of the character model, and v′ _i can be obtained by formula (1).

According to the above two constraints (formulas (2) and (3)), the position of the joint point can be obtained by the nonlinear optimization method, using the relative position weight to constrain the relative position of the joint point and the surrounding mesh vertices, affine transformation, and The linear skinning algorithm is used to solve the problem, which can determine the bone elongation ratio s of the bones of the character model relative to the bones of the template model, the rotation angle q of the bones, and the vertices of the skin mesh of the character model relative to the vertices of the skin mesh of the template model. The displacement compensation vo _i these three parameters, and determine the bones of the character model through these three parameters.

The nonlinear optimization method may include gradient descent method, Newton method, quasi-Newton method, LM algorithm, and the like.

In a possible implementation manner, determining the bones of the character model to be created according to the bone elongation ratio and the bone rotation angle and the bones of the template model, including: according to the bone elongation ratio, the The skeleton rotation angle and the skeleton of the template model determine the skeleton of the deformed template model; the skin mesh of the template model is modified according to the displacement compensation and the skin weight of the template model; after the modification When the degree of coincidence between the shape of the skin mesh of the template model and the shape of the skin mesh of the character model to be created is greater than a predetermined threshold, the skeleton of the deformed template model is nested into the character to be created model, so as to determine the skeleton of the character model to be created.

The skeleton of the template model can be deformed by stretching and rotating to determine the skeleton of the deformed template model; and the skin mesh of the template model can be stretched by referring to the skeleton of the deformed template model. , so as to form the skin mesh of the deformed template model. At this time, the shape and posture of the skin mesh of the deformed template model approach the skin mesh of the character model.

In a possible implementation manner, according to any embodiment of the present invention, the skin weight of the character model to be created is determined according to the skin weight of the template model.

Among them, the skin weight of the character model can be obtained by the skin weight of the template model.

For example, the skin weight of the template model can be directly used as the skin weight of the character model, or the skin weight of the template model can be adjusted as needed to be used as the skin weight of the character model.

In a possible implementation, referring to the bones of the deformed template model, the skin mesh of the template model can be stretched and deformed according to the skin weight and displacement compensation to form the skin mesh of the deformed template model. The shape of the skin mesh of the template model is matched with the shape of the skin mesh of the character model to be created. When the degree of coincidence of the matching is greater than the set predetermined threshold, the bones of the deformed template model are nested into the to-be-created model. character model, so as to determine the skeleton of the character model to be created.

Due to the simple use of bone-driven skin mesh to deform the character model, there are defects in practical application. For example, when the bone drives the shoulder joint movement, the skin mesh of the shoulder will produce a collapsed visual effect, and the bone drives the elbow joint movement. , the volume of the elbow will be missing and so on. Various defects of the skin mesh of the skeletal skinning animation can be repaired by trimming. The template model has preset a set of modifications corresponding to each joint carved by the technicians. The modifications in the template model need to be transmitted to the character synchronously. on the model.

In a possible implementation manner, in step S104, determining the modification of the character model to be created according to the modification of the template model includes: determining each of the skin meshes of the character model to be created. The first side vector matrix corresponding to the grid unit in the initial state, and the second side vector matrix corresponding to each grid unit in the skin mesh of the character model to be created after the joints are rotated, the first side vector The matrix and the second edge vector matrix are determined from the edge vectors and face normals of the corresponding grid cells.

In a possible implementation manner, during the modification and migration process, the flip transformation matrix of each grid unit in the skin grid of the character model to be created is made to be the same as that of each grid unit in the skin grid of the template model. The flip transformation matrix is the same.

According to this embodiment, the character is determined based on the same constraints as the flip transformation matrix of each grid unit in the skin mesh of the character model to be created and the flip transformation matrix of each grid cell in the skin mesh of the template model The edge vector matrix of the mesh unit of the model, so as to realize the automatic transfer of template model modification to role model modification, save the labor cost and time cost of manual migration of technicians, and improve the efficiency of making role models. Through the modification of the character model, various defects of the character model when it is transformed between different states are solved, so that the character model can more accurately simulate the biological movement form of the real world. By constraining the flip transformation matrix of each grid unit of the character model and the template model to be the same, it is ensured that the modifications pre-sculpted by the technicians on the template model can be transferred to the character model more completely and accurately.

In a possible implementation manner, the inversion transformation matrix of each grid unit in the skin mesh of the character model to be created is made the same as the inversion transformation matrix of the grid unit adjacent to the grid unit.

According to this embodiment, by further constraining the flip transformation matrix of each grid unit of the character model to be the same as the flip transformation matrix of the grid unit adjacent to the grid unit, the surface of the character model is made smoother and smoother, with better performance. visual effects. At the same time, through automatic migration and minor repairs by technicians, the character model can more accurately repair various defects of the skin mesh of the skeletal skinning animation, making the structure and shape of the character model more artistic.

Since the template model is transformed from the initial static state to the motion state of bone joint rotation, the modified skin mesh will change accordingly, which can be represented by flipping the transformation matrix Q. Take the grid unit as a triangular surface as an example, where M is the edge vector matrix of the triangular surface, which is a 3×3 matrix, M _i represents the i-th triangular surface,

are the coordinates of the three vertices on the i-th triangular face on the skin mesh, n _i is the face normal on the i-th triangular face, and two edge vectors

And the face normal _ni represents the edge vector matrix corresponding to the triangular face. The flip transformation matrix Q _i is a 3×3 matrix, which represents the flip transformation of the triangular face on the skin mesh,

Indicates that the template model adds the edge vector matrix corresponding to the i-th triangular face of the modified skin mesh after the bones are rotated (that is, the second edge vector matrix of the template model),

Indicates the edge vector matrix corresponding to the ith triangular face of the skin mesh in the initial state of the template model (ie, the first edge vector matrix of the template model). The flip transformation matrix Q can be obtained by multiplying the first side vector matrix and the second side vector matrix inverse matrix.

The flip transformation of the i-th modified triangle surface of the template model can be obtained by the above method, according to the first side vector matrix of the upper triangular surface of the skin grid of the template model and the second side vector matrix of the upper triangle surface of the skin grid of the template model. matrix

Similarly, according to the first side vector matrix of the upper triangular face of the skin mesh of the character model and the second side vector matrix of the upper triangular face of the skin mesh of the character model, the flip transformation matrix of the i-th modified triangular face of the character model is obtained.

Wherein, the first side vector matrix of the upper triangle surface of the skin mesh of the template model and the upper triangle surface of the skin mesh of the character model can be obtained according to the skin mesh data of the template model and the character model in the initial state; the skin mesh of the template model The second side vector matrix of the upper triangle surface of the grid can be obtained according to the skin mesh data of the template model after bone rotation and modification. At this time, the second side vector matrix of the upper triangle surface of the skin mesh of the character model is required. Unknown variable.

Due to the existence of the same constraints of the flip transformation matrix of each grid unit of the role model and the template model. constraint

The two triangular face flip matrices are the same, where,

Represents the flip transformation matrix of the i-th modified triangular face of the character model,

Represents the flip transformation matrix of the ith modified triangular face of the template model.

Because the shapes of the template model and the character model are different, when the modification calculated by the above constraints is transmitted to the character model, the modification surface of the character model will be uneven.

In order to make the modified surface of the character model smoother and smoother, in a possible implementation manner, the flip transformation matrix of each grid unit in the skin mesh of the character model and the flip transformation of the grid unit adjacent to the grid unit The matrix is the same. Among them, in order to make the modified surface of the character model after modification migration smooth and complete, you can constrain

The two triangular face flip matrices are the same. in,

Represents the flip transformation matrix of the adjoining triangular faces of the i-th trimmed triangular face of the character model.

According to the above two constraints, a large-scale equation system can be established to solve, and the edge vector matrix M of the modified triangle surface of the character model can be determined. For example, the modification of the character model can be determined by solving a large-scale sparse matrix, that is, the The second edge vector matrix in the text. The methods of solving large sparse matrices can include LU decomposition, QR decomposition, iterative solution, etc.

FIG. 2 shows a schematic diagram of an application scenario of a method for creating a virtual character model according to an embodiment of the present disclosure. As shown in FIG. 2 , a plug-in may be embedded in the animation production software to implement the above-mentioned method of the embodiment of the present disclosure. Template models A, B, and C can be set in advance. When users use animation production software to create a character model, they can import or select a template model A that is similar in shape to the character model. The template model A can be adjusted appropriately through the software. The shape is deformed to the shape of the character model to match the topology and shape of the two. Next, the user can activate the plug-in through the software, execute the method described above, and transfer the bones, skin weights, and modifications of the template model to the character model, and then fine-tune the character model obtained after the migration by the user. Get the final character model.

The software tool implemented based on the method of the embodiment of the present disclosure has good interactivity, and the operation is simple and efficient. Users only need to perform simple weight adjustment and template selection to generate initial binding bones with one click, and then perform fine mesh weight adjustment on the generated model to obtain a rough bone binding model. For this model , the software tool can automatically calculate the corresponding modification data, and the user can obtain a complete 3D human skeleton binding model by refining the generated modification results.

FIG. 3 shows a block diagram of an apparatus for creating a virtual character model according to an embodiment of the present disclosure. As shown in FIG. 3, the virtual character model creation apparatus 10 may include:

a first character model determination module 11, configured to determine a character model to be created, the character model to be created at least includes a skin mesh;

The template model determination module 12 is configured to determine a template model according to the character model to be created, where the template model includes a skin mesh, a bone matched with the skin mesh, and a mask corresponding to the skin mesh. Skin weight and modification corresponding to each joint point;

The second character model determination module 13 is configured to determine the bones and skin weights of the character model to be created according to the skin meshes, bones, and skin weights of the template model;

A third character model determining module 14, configured to determine the modification of the character model to be created according to the modification of the template model;

The character model creation module 15 is used for creating a character model according to the skin mesh, skeleton, skin weight and modification of the character model to be created.

In a possible implementation manner, the apparatus 10 further includes:

In a possible implementation manner, the second role model determining module 13 includes:

In a possible implementation manner, the third role model determining module 14 includes:

In a possible implementation manner, the apparatus 10 further includes:

An embodiment of the present disclosure provides an apparatus for creating a virtual character model, including: a processor; a memory for storing instructions executable by the processor; wherein the processor is configured to implement the above method when executing the instructions.

The embodiments of the present disclosure provide a non-volatile computer-readable storage medium, on which computer program instructions are stored, and when the computer program instructions are executed by a processor, the foregoing method is implemented.

FIG. 4 is a block diagram of an electronic device 800 for creating a virtual character model according to an exemplary embodiment. For example, electronic device 800 may be a mobile phone, computer, digital broadcast terminal, messaging device, game console, tablet device, medical device, fitness device, personal digital assistant, and the like.

4, the electronic device 800 may include one or more of the following components: a processing component 802, a memory 804, a power supply component 806, a multimedia component 808, an audio component 810, an input/output (I/O) interface 812, a sensor component 814 , and the communication component 816 .

The processing component 802 generally controls the overall operation of the electronic device 800, such as operations associated with display, phone calls, data communications, camera operations, and recording operations. The processing component 802 can include one or more processors 820 to execute instructions to perform all or some of the steps of the methods described above. Additionally, processing component 802 may include one or more modules that facilitate interaction between processing component 802 and other components. For example, processing component 802 may include a multimedia module to facilitate interaction between multimedia component 808 and processing component 802.

Memory 804 is configured to store various types of data to support operation at electronic device 800 . Examples of such data include instructions for any application or method operating on electronic device 800, contact data, phonebook data, messages, pictures, videos, and the like. Memory 804 may be implemented by any type of volatile or nonvolatile storage device or combination thereof, such as static random access memory (SRAM), electrically erasable programmable read only memory (EEPROM), erasable Programmable Read Only Memory (EPROM), Programmable Read Only Memory (PROM), Read Only Memory (ROM), Magnetic Memory, Flash Memory, Magnetic or Optical Disk.

Power supply assembly 806 provides power to various components of electronic device 800 . Power supply components 806 may include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power to electronic device 800 .

Multimedia component 808 includes a screen that provides an output interface between the electronic device 800 and the user. In some embodiments, the screen may include a liquid crystal display (LCD) and a touch panel (TP). If the screen includes a touch panel, the screen may be implemented as a touch screen to receive input signals from a user. The touch panel includes one or more touch sensors to sense touch, swipe, and gestures on the touch panel. The touch sensor may not only sense the boundaries of a touch or swipe action, but also detect the duration and pressure associated with the touch or swipe action. In some embodiments, the multimedia component 808 includes a front-facing camera and/or a rear-facing camera. When the electronic device 800 is in an operation mode, such as a shooting mode or a video mode, the front camera and/or the rear camera may receive external multimedia data. Each of the front and rear cameras can be a fixed optical lens system or have focal length and optical zoom capability.

Audio component 810 is configured to output and/or input audio signals. For example, audio component 810 includes a microphone (MIC) that is configured to receive external audio signals when electronic device 800 is in operating modes, such as calling mode, recording mode, and voice recognition mode. The received audio signal may be further stored in memory 804 or transmitted via communication component 816 . In some embodiments, audio component 810 also includes a speaker for outputting audio signals.

The I/O interface 812 provides an interface between the processing component 802 and a peripheral interface module, such as a keyboard, a click wheel, a button, and the like. These buttons may include, but are not limited to: home button, volume buttons, start button, and lock button.

Sensor assembly 814 includes one or more sensors for providing status assessment of various aspects of electronic device 800 . For example, the sensor assembly 814 can detect the on/off state of the electronic device 800, the relative positioning of the components, such as the display and the keypad of the electronic device 800, the sensor assembly 814 can also detect the electronic device 800 or one of the electronic device 800 Changes in the position of components, presence or absence of user contact with the electronic device 800 , orientation or acceleration/deceleration of the electronic device 800 and changes in the temperature of the electronic device 800 . Sensor assembly 814 may include a proximity sensor configured to detect the presence of nearby objects in the absence of any physical contact. Sensor assembly 814 may also include a light sensor, such as a CMOS or CCD image sensor, for use in imaging applications. In some embodiments, the sensor assembly 814 may also include an acceleration sensor, a gyroscope sensor, a magnetic sensor, a pressure sensor, or a temperature sensor.

Communication component 816 is configured to facilitate wired or wireless communication between electronic device 800 and other devices. Electronic device 800 may access wireless networks based on communication standards, such as WiFi, 2G or 3G, or a combination thereof. In one exemplary embodiment, the communication component 816 receives broadcast signals or broadcast related information from an external broadcast management system via a broadcast channel. In an exemplary embodiment, the communication component 816 also includes a near field communication (NFC) module to facilitate short-range communication. For example, the NFC module may be implemented based on radio frequency identification (RFID) technology, infrared data association (IrDA) technology, ultra-wideband (UWB) technology, Bluetooth (BT) technology and other technologies.

In an exemplary embodiment, electronic device 800 may be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable A programmed gate array (FPGA), controller, microcontroller, microprocessor or other electronic component implementation is used to perform the above method.

In an exemplary embodiment, a non-volatile computer-readable storage medium, such as a memory 804 comprising computer program instructions executable by the processor 820 of the electronic device 800 to perform the above method is also provided.

Fig. 5 is a block diagram of an apparatus 1900 for creating a virtual character model according to an exemplary embodiment. For example, the apparatus 1900 may be provided as a server. 5, apparatus 1900 includes processing component 1922, which further includes one or more processors, and a memory resource represented by memory 1932 for storing instructions executable by processing component 1922, such as applications. An application program stored in memory 1932 may include one or more modules, each corresponding to a set of instructions. Additionally, the processing component 1922 is configured to execute instructions to perform the above-described methods.

The device 1900 may also include a power supply assembly 1926 configured to perform power management of the device 1900, a wired or wireless network interface 1950 configured to connect the device 1900 to a network, and an input output (I/O) interface 1958. Device 1900 may operate based on an operating system stored in memory 1932, such as Windows Server™, Mac OS X™, Unix™, Linux™, FreeBSD™ or the like.

In an exemplary embodiment, a non-volatile computer-readable storage medium is also provided, such as memory 1932 comprising computer program instructions executable by processing component 1922 of apparatus 1900 to perform the above-described method.

The present disclosure may be a system, method and/or computer program product. The computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of the present disclosure.

A computer-readable storage medium may be a tangible device that can hold and store instructions for use by the instruction execution device. The computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples (non-exhaustive list) of computer readable storage media include: portable computer disks, hard disks, random access memory (RAM), read only memory (ROM), erasable programmable read only memory (EPROM) or flash memory), static random access memory (SRAM), portable compact disk read only memory (CD-ROM), digital versatile disk (DVD), memory sticks, floppy disks, mechanically coded devices, such as printers with instructions stored thereon Hole cards or raised structures in grooves, and any suitable combination of the above. Computer-readable storage media, as used herein, are not to be construed as transient signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (eg, light pulses through fiber optic cables), or through electrical wires transmitted electrical signals.

The computer readable program instructions described herein may be downloaded to various computing/processing devices from a computer readable storage medium, or to an external computer or external storage device over a network such as the Internet, a local area network, a wide area network, and/or a wireless network. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer-readable program instructions from a network and forwards the computer-readable program instructions for storage in a computer-readable storage medium in each computing/processing device .

Computer program instructions for carrying out operations of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or instructions in one or more programming languages. Source or object code, written in any combination, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as the "C" language or similar programming languages. The computer readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer, or entirely on the remote computer or server implement. In the case of a remote computer, the remote computer may be connected to the user's computer through any kind of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (eg, using an Internet service provider through the Internet connect). In some embodiments, custom electronic circuits, such as programmable logic circuits, field programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), can be personalized by utilizing state information of computer readable program instructions. Computer readable program instructions are executed to implement various aspects of the present disclosure.

Aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions.

These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer or other programmable data processing apparatus to produce a machine that causes the instructions when executed by the processor of the computer or other programmable data processing apparatus , resulting in means for implementing the functions/acts specified in one or more blocks of the flowchart and/or block diagrams. These computer readable program instructions can also be stored in a computer readable storage medium, these instructions cause a computer, programmable data processing apparatus and/or other equipment to operate in a specific manner, so that the computer readable medium storing the instructions includes An article of manufacture comprising instructions for implementing various aspects of the functions/acts specified in one or more blocks of the flowchart and/or block diagrams.

Computer readable program instructions can also be loaded onto a computer, other programmable data processing apparatus, or other equipment to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other equipment to produce a computer-implemented process , thereby causing instructions executing on a computer, other programmable data processing apparatus, or other device to implement the functions/acts specified in one or more blocks of the flowcharts and/or block diagrams.

The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more functions for implementing the specified logical function(s) executable instructions. In some alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures. For example, two blocks in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It is also noted that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented in dedicated hardware-based systems that perform the specified functions or actions , or can be implemented in a combination of dedicated hardware and computer instructions.

Various embodiments of the present disclosure have been described above, and the foregoing descriptions are exemplary, not exhaustive, and not limiting of the disclosed embodiments. Numerous modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the various embodiments, the practical application or technical improvement over the technology in the marketplace, or to enable others of ordinary skill in the art to understand the various embodiments disclosed herein.

Claims

A method for creating a virtual character model, characterized in that the method comprises:

determining a character model to be created, the character model to be created at least includes a skin mesh;

According to the character model to be created, a template model is determined, and the template model includes a skin mesh, a bone matched with the skin mesh, a skin weight corresponding to the skin mesh, and each joint point. modification;

Determine the bones and skin weights of the character model to be created according to the skin meshes, bones, and skin weights of the template model;

According to the modification of the template model, determine the modification of the character model to be created;

A character model is created according to the skin mesh, bones, skin weights and modifications of the character model to be created.
The method according to claim 1, wherein the method further comprises:

In the case that the topology of the skin mesh of the character model to be created is inconsistent with the topology of the skin mesh of the template model, determine that the topology of the skin mesh of the template model is that of the character model to be created. the topology of the skin mesh;

The shape of the skin mesh of the template model is modified according to the shape of the skin mesh of the character model to be created.
The method according to claim 1, wherein determining the bones and skin weights of the character model to be created according to skin meshes, bones, and skin weights of the template model, comprising:

Determine the bone elongation ratio and the bone rotation angle of the bones of the character model to be created relative to the bones of the template model, and the vertices of the skin mesh of the character model to be created relative to the skin of the template model. Displacement compensation of the vertices of the mesh;

The bones of the character model to be created are determined according to the bone elongation ratio and the bone rotation angle and the bones of the template model.
The method according to claim 3, wherein the bone elongation ratio, the bone rotation angle of the bones of the character model to be created relative to the bones of the template model, and the bone rotation angle of the character model to be created are determined. The displacement compensation of the vertices of the skin mesh relative to the vertices of the skin mesh of the template model, including:

The joint point coordinates of the template model after bone stretching and rotation obtained according to the bone elongation ratio and the bone rotation angle are compared with those obtained according to the bone elongation ratio, the bone rotation angle, and the displacement compensation. The joint point coordinates obtained by weighting the skin mesh vertex coordinates around the joint points of the template model after the bone stretching and rotation are the same;

After the bones are stretched and rotated, the skin mesh vertex coordinates of the template model are the same as the skin mesh vertex coordinates of the character model to be created;

Wherein, after the bones are stretched and rotated, the coordinates of the skin mesh vertices of the template model are obtained according to the stretch ratio of the bones, the rotation angle of the bones and the displacement compensation.
The method according to claim 3, wherein determining the bones of the character model to be created according to the bone elongation ratio and the bone rotation angle and the bones of the template model, comprising:

Determine the skeleton of the deformed template model according to the skeleton elongation ratio, the skeleton rotation angle and the skeleton of the template model;

modifying the skin mesh of the template model according to the displacement compensation and the skin weight of the template model;

When the degree of coincidence between the shape of the skin mesh of the modified template model and the shape of the skin mesh of the character model to be created is greater than a predetermined threshold, nest the bones of the deformed template model into the to-be-created character model. In the created character model, the bones of the character model to be created are determined.
The method according to claim 1, wherein determining the modification of the character model to be created according to the modification of the template model, comprising:

Determine the first side vector matrix corresponding to each grid unit in the skin grid of the character model to be created in the initial state, and each grid unit in the skin grid of the character model to be created after the joints are rotated The corresponding second edge vector matrix, the first edge vector matrix and the second edge vector matrix are determined according to the edge vector and the surface normal of the corresponding grid unit.
The method according to claim 6, wherein the first edge vector matrix corresponding to each grid unit in the skin grid of the character model to be created in an initial state is determined, and the The second edge vector matrix corresponding to each mesh element in the skin mesh of the created character model, including:

Make the flip transformation matrix of each grid unit in the skin grid of the character model to be created the same as the flip transformation matrix of each grid unit in the skin grid of the template model;

Wherein, the flip transformation matrix of each grid unit in the skin grid of the character model to be created is based on the first side vector matrix and the first edge vector matrix of each grid unit in the skin grid of the character model to be created. The second side vector matrix is obtained, and the flip transformation matrix of each grid unit in the skin grid of the template model is based on the first side vector matrix and the second side vector of each grid unit in the skin grid of the template model. matrix is obtained.
The method according to claim 6, wherein the first edge vector matrix corresponding to each grid unit in the skin grid of the character model to be created in an initial state is determined, and the The second edge vector matrix corresponding to each grid unit in the skin grid of the created character model, including:

Make the flip transformation matrix of each grid unit in the skin grid of the character model to be created the same as the flip transformation matrix of the grid unit adjacent to the grid unit;

Wherein, the flip transformation matrix of the character model to be created is obtained according to the first side vector matrix and the second side vector matrix of each grid unit in the skin mesh of the character model to be created.
The method according to any one of claims 1 to 4, wherein the skin weight of the character model to be created is determined according to the skin weight of the template model.
An apparatus for creating a virtual character model, wherein the apparatus comprises:

a first character model determination module, configured to determine a character model to be created, where the character model to be created at least includes a skin mesh;

A template model determination module, configured to determine a template model according to the character model to be created, where the template model includes a skin mesh, a skeleton matching the skin mesh, and a skin corresponding to the skin mesh Weights and modifications corresponding to each joint point;

A second character model determination module, configured to determine the bones and skin weights of the character model to be created according to the skin meshes, bones, and skin weights of the template model;

a third role model determining module, configured to determine the modification of the to-be-created role model according to the modification of the template model;

The character model creation module is used for creating a character model according to the skin mesh, skeleton, skin weight and modification of the character model to be created.
An electronic device for creating a virtual character model, comprising:

processor;

memory for storing processor-executable instructions;

wherein the processor is configured to, when executing the instructions, implement the method of any one of claims 1 to 8.
A non-volatile computer-readable storage medium on which computer program instructions are stored, characterized in that, when the computer program instructions are executed by a processor, the method described in any one of claims 1 to 8 is implemented.