CN104392484B - A kind of Three-dimension Tree modeling method and device - Google Patents

Abstract

The present invention is applicable to the field of computer graphics, and provides a three-dimensional tree modeling method and device, including: partially intercepting an existing three-dimensional tree model to obtain multiple model components; The components are parameterized so that the multiple model components are matched with each other; the multiple model components that are matched with each other are interpolated to generate connection components between adjacent model components. The present invention mainly cuts out several model components from the existing tree model for adjustment and combination, and generates the connection parts between different model components through an interpolation algorithm, so as to generate a new three-dimensional tree model. The modeling process does not involve three-dimensional data The collection greatly simplifies the data processing link in the modeling process and improves the efficiency of 3D tree modeling.

Description

A three-dimensional tree modeling method and device

technical field

The invention belongs to the field of computer graphics, in particular to a three-dimensional tree modeling method and device.

Background technique

Tree modeling has broad application prospects in technical fields such as urban three-dimensional modeling, computer game scene design, and virtual reality. Most of the existing 3D tree modeling is based on 3D data acquisition. It is necessary to first obtain 3D data information of trees, for example, use a 3D laser scanner to collect 3D point clouds of trees, or use cameras to collect images from multiple perspectives of trees, etc. etc., and then use the 3D reconstruction method to build a 3D tree model. However, most of the above three-dimensional data acquisition methods require the use of professional three-dimensional data acquisition equipment, and the data processing process is complicated and time-consuming, which makes the three-dimensional tree modeling process inefficient.

Contents of the invention

The purpose of the embodiments of the present invention is to provide a three-dimensional tree modeling method, aiming at solving the problem of low efficiency of three-dimensional tree modeling at present.

The embodiment of the present invention is achieved like this, a kind of three-dimensional tree modeling method, comprises:

Partially intercept the existing 3D tree model to obtain multiple model components;

performing parameter setting on the acquired multiple model components, so that the multiple model components are matched with each other;

Interpolation processing is performed on the multiple model components that are matched with each other to generate connection components between adjacent model components.

Another object of the embodiments of the present invention is to provide a three-dimensional tree modeling device, including:

The intercepting unit is used for partially intercepting the existing three-dimensional tree model to obtain multiple model components;

a setting unit, configured to set parameters for the acquired multiple model components, so that the multiple model components are matched with each other;

An interpolation unit, configured to perform interpolation processing on the plurality of model components that are matched with each other, and generate connection components between adjacent model components.

In the embodiment of the present invention, a new three-dimensional tree model is generated by intercepting several model components from the existing tree model, adjusting and combining them, and generating the connection parts between different model components through an interpolation algorithm. The modeling process does not involve The acquisition of 3D data greatly simplifies the data processing link in the modeling process and improves the efficiency of 3D tree modeling.

Description of drawings

Fig. 1 is the implementation flowchart of the three-dimensional tree modeling method provided by the embodiment of the present invention;

Fig. 2 is an example diagram of a handheld laser scanner provided by an embodiment of the present invention;

Fig. 3 is an example diagram of an existing three-dimensional tree model provided by an embodiment of the present invention;

Fig. 4 is an example diagram of a three-dimensional tree model and its corresponding three-dimensional skeleton provided by an embodiment of the present invention;

Fig. 5 is an example diagram of partial interception on an existing three-dimensional tree model provided by an embodiment of the present invention;

Fig. 6 is an example diagram of a model component provided by an embodiment of the present invention;

FIG. 7 is a specific implementation flowchart of the three-dimensional tree modeling method S103 provided by the embodiment of the present invention;

Fig. 8 is an example diagram of a hermit curve provided by an embodiment of the present invention;

Fig. 9 is an exemplary diagram of the corresponding relationship between peripheral vertices of two cross-sections provided by an embodiment of the present invention;

Fig. 10 is a two-dimensional illustration of an interpolation result provided by an embodiment of the present invention between corresponding points of two cross-sections;

Fig. 11 is a three-dimensional example diagram of interpolation results corresponding to different hermit curves provided by an embodiment of the present invention;

Fig. 12 is an example diagram of matching a real geometric surface to a generated tree model provided by an embodiment of the present invention;

Fig. 13 is an example diagram of the effect of adding branches and leaves to the tree model provided by the embodiment of the present invention;

Fig. 14 is an example diagram of three-dimensional tree modeling provided by an embodiment of the present invention;

Fig. 15 is a structural block diagram of a three-dimensional tree modeling device provided by an embodiment of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

In the embodiment of the present invention, a new three-dimensional tree model is generated by intercepting several model components from the existing tree model, adjusting and combining them, and generating the connection parts between different model components through an interpolation algorithm. The modeling process does not involve The acquisition of 3D data greatly simplifies the data processing link in the modeling process and improves the efficiency of 3D tree modeling.

Fig. 1 shows the implementation process of the three-dimensional tree modeling method provided by the embodiment of the present invention, which is described in detail as follows:

In S101, a part of the existing three-dimensional tree model is intercepted to obtain multiple model components.

Before S101, a 3D tree model database can be established in advance, for example, using a hand-held laser scanner as shown in Figure 2 to collect 3D point clouds of different types and shapes of trees in reality, and use The method of Poisson reconstruction is used to obtain the three-dimensional tree model of these trees (Fig. 3 shows part of the pre-established three-dimensional tree model). While obtaining the three-dimensional tree models of these trees, the tree model skeleton generation method can also be used to generate the three-dimensional skeletons of these trees. The three-dimensional skeleton is used to express the direction of the branches of the trees, as shown in Figure 4. 3D tree model, and the right picture is the 3D skeleton corresponding to the 3D tree model.

The establishment process of the above-mentioned 3D tree model database can be completed by professional technicians in the field of 3D modeling, and the database is opened to users as a modeling material library.

Fig. 5 is a schematic diagram of partial interception on an existing three-dimensional tree model.

Fig. 6 shows several model components obtained by partially intercepting an existing 3D tree model.

In S102, parameter setting is performed on the multiple acquired model components, so that the multiple model components are matched with each other.

In this embodiment, multiple model components are matched with each other, which means that parameters such as the size and direction of the multiple model components and the link relationship between the multiple model components are all configured on appropriate values, So that these multiple model components can be placed in a tree in a reasonable and orderly manner.

Among them, the link relationship between multiple model components is used to represent the sequence relationship of the placement positions of these multiple model components in the 3D tree model to be created, for example, from the top of the tree to the root of the tree, place model components 1, Model Component 2, Model Component 3, and Model Component 4. Through this link relationship, the model components adjacent to one model component can be determined. As an implementation manner, the link relationship can be generated by specifying by the user.

Preferably, a graphic system for human-computer interaction can be established, and the parameter setting of these multiple model components can be realized through visual operation. Specifically, the computer background uses the opengl projection algorithm to project the model components and three-dimensional coordinates to the screen coordinates, thereby corresponding the three-dimensional coordinates and the two-dimensional coordinates of the screen, to combine keyboard, mouse or gesture operations (such as moving, rotating, zooming) and other operations) to realize the parameter setting of the model component. Under the interactive graphics system, model components can be placed sequentially by dragging and dropping, and the system background automatically establishes a link relationship between two adjacent model components according to the placement position of the model components.

In S103, an interpolation process is performed on the multiple model components that are matched with each other to generate connection components between adjacent model components.

Since the model components obtained in S101 are discrete, interpolation processing needs to be performed on this part of the discrete model components, and the remaining parts between adjacent model components need to be connected and completed.

As shown in Figure 7, S103 is specifically:

In S701, a Hermit curve is generated by interpolation between adjacent model components.

Specifically, tree skeletons corresponding to adjacent model components may be interpolated to generate corresponding Hermit curves. The generated hermit curve is used to represent the direction of the branches between two adjacent model components, and after the hermit curve is generated, the curvature of the hermit curve can be adjusted to change the direction of the above branches, so that the direction of the final generated branches Consistent with modeling needs.

Figure 8 is an example diagram of the hermit curve generated by S701. As shown in Figure 8, the straight lines in the left and right figures are used to represent the link relationship of the model components shown in the figure, and the curve is the hermit curve. It can be seen that, The curvatures of the Hermit curves generated in the left and right images are different.

In S702, establish a two-to-two correspondence relationship between peripheral vertices of the first cross-section and the second cross-section, the first cross-section and the second cross-section are adjacent cross-sections of the adjacent model components.

After creating the hermit curves, it is necessary to render the branches between two adjacent model components. First, in S702, establish the corresponding relationship between the vertices on the periphery of adjacent cross-sections. Specifically, starting from a certain point on two adjacent cross-sections at the same time, determine two points in sequence clockwise or counterclockwise. Correspondence points between cross sections.

FIG. 9 is a two-dimensional schematic diagram of corresponding points between the first cross section and the second cross section acquired in S702. According to the skeleton direction of the model, the first cross section 91 is located above the second cross section 92. The dotted lines indicate the correspondence between the partial peripheral vertices of the first cross section 91 and the second cross section 92 .

Among them, the better corresponding relationship is: the sum of the squares of the displacements between all pairwise corresponding peripheral vertices is the smallest, which can ensure that the deformation of the cross-section interpolated between corresponding points in the subsequent processing is the smallest, and can keep the branches. Dry twisted shape.

In S703, interpolation is performed between corresponding points of the first cross section and the second cross section.

Fig. 10 is a two-dimensional illustration of the interpolation result of interpolation between corresponding points according to the corresponding relationship in Fig. 9. It can be seen that the interpolation between the first cross-section and the second cross-section generates peripheral vertices of three cross-sections .

In S704, the interpolation result is moved and rotated along the corresponding Hermit curve to generate a connection component between the first cross section and the second cross section.

In this step, the curvature of the peripheral vertices generated by interpolation and the corresponding Hermit curves are kept unchanged, and the peripheral vertices generated by interpolation are moved and rotated along their corresponding Hermit curve segments, thereby generating the first cross-section and the second The connection component between the cross sections, that is, the branch part between the first cross section and the second cross section.

FIG. 11 shows interpolation results corresponding to two different hermit curves generated according to the embodiment shown in FIG. 7 .

In the embodiment of the present invention, the connected components of the tree model generated only by the interpolation processing in S103 are too smooth, and lack details such as bumps and wrinkles in real trees. The surface is deformed to match the connected part generated in S103. Specifically, both the connected component and the existing 3D tree model are represented as a common cylinder, the radius and relative potential difference between the two are recorded, the size of the existing 3D tree model is scaled to the size of the connected component, and Move to the location of the connected components and maintain the existing 3D tree model's potential difference, so that a 3D tree model with real surface geometric details can be obtained.

As shown in Fig. 12, from left to right are the connected components obtained in S103, some branches of the existing 3D tree model, and connected components obtained after deformation matching.

As shown in Figure 13, the left picture is the 3D tree model obtained through the above steps. Finally, the automatic linear system can be used to render the small branches and leaves on the 3D tree model, which has increased the realism of the tree. 13 The high-fidelity 3D tree model shown in the right figure.

From left to right in Fig. 14 are the matched model components after S101 and S102, the 3D tree model generated after interpolation, and the rendering effect after adding twigs and leaves.

In the embodiment of the present invention, a new three-dimensional tree model is generated by intercepting several model components from the existing tree model, adjusting and combining them, and generating the connection parts between different model components through an interpolation algorithm. The modeling process does not involve The acquisition of 3D data greatly simplifies the data processing link in the modeling process and improves the efficiency of 3D tree modeling.

FIG. 15 shows a structural block diagram of a three-dimensional tree modeling device provided by an embodiment of the present invention. For convenience of description, only parts related to this embodiment are shown.

Referring to Figure 15, the device includes:

The intercepting unit 1501 partially intercepts the existing 3D tree model to obtain multiple model components.

The setting unit 1502 is configured to set parameters for the multiple acquired model components, so as to match the multiple model components with each other.

The interpolation unit 1503 performs interpolation processing on the multiple model components that are matched with each other to generate connection components between adjacent model components.

Optionally, the setting unit 1502 is specifically configured to:

The size and direction of the model components and the link relationship among the multiple model components are set.

Optionally, the interpolation unit includes:

The curve generation sub-unit generates a Hermit curve between adjacent model components through interpolation.

Correspondence establishment sub-units, establishing pairwise correspondences between the first cross-section and the peripheral vertices of the second cross-section, the first cross-section and the second cross-section are adjacent cross-sections of the adjacent model components .

The interpolation subunit performs interpolation between corresponding points of the first cross-section and the second cross-section.

The connecting component generating subunit is used to move and rotate the interpolation result along the corresponding Hermit curve to generate the connecting component between the first cross-section and the second cross-section.

Optionally, the corresponding relationship satisfies: the sum of squares of displacements between all pairwise corresponding peripheral vertices is minimum.

Optionally, the device also includes:

The geometric surface processing unit deforms the geometric surface of the existing three-dimensional tree model and matches it to the connecting component.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (8)

1. A three-dimensional tree modeling method, characterized in that, comprising: Partially intercept the existing 3D tree model to obtain multiple model components; performing parameter setting on the acquired multiple model components, so that the multiple model components are matched with each other; Perform interpolation processing on the multiple model components that are matched with each other, and generate connection components between adjacent model components, including: generating hermit curves by interpolation between adjacent said model components; Establishing a two-to-two correspondence relationship between the peripheral vertices of the first cross-section and the second cross-section, the first cross-section and the second cross-section are adjacent cross-sections adjacent to the model component; interpolating between corresponding points of the first cross-section and the second cross-section; The interpolation result is moved and rotated along the corresponding Hermit curve to generate a connection component between the first cross-section and the second cross-section. 2. The method according to claim 1, wherein said parameter setting of said plurality of model components obtained comprises: The size and direction of the model components and the link relationship among the multiple model components are set. 3 . The method according to claim 1 , wherein the corresponding relationship satisfies: the sum of squares of displacements between all pairwise corresponding peripheral vertices is minimum. 4 . 4. The method according to any one of claims 1-3, wherein the method further comprises: The geometric surface of the existing three-dimensional tree model is deformed and matched to the connecting component. 5. A three-dimensional tree modeling device, characterized in that, comprising: The intercepting unit is used for partially intercepting the existing three-dimensional tree model to obtain multiple model components; a setting unit, configured to set parameters for the acquired multiple model components, so that the multiple model components are matched with each other; An interpolation unit, configured to perform interpolation processing on the plurality of model components that are matched with each other, and generate connection components between adjacent model components; The interpolation unit includes: A curve generation subunit is used to generate a hermit curve by interpolation between adjacent model components; A corresponding relationship establishing subunit, configured to establish a two-to-two corresponding relationship between the peripheral vertices of the first cross-section and the second cross-section, the first cross-section and the second cross-section are adjacent to the model component cross section; an interpolation subunit for interpolating between corresponding points of the first cross-section and the second cross-section; The connecting component generating subunit is used to move and rotate the interpolation result along the corresponding Hermit curve to generate the connecting component between the first cross-section and the second cross-section. 6. The device according to claim 5, wherein the setting unit is specifically used for: The size and direction of the model components and the link relationship among the multiple model components are set. 7 . The device according to claim 5 , wherein the corresponding relationship satisfies: a sum of squares of displacements between all pairwise corresponding peripheral vertices is minimum. 8 . 8. The device according to any one of claims 5-7, wherein the device further comprises: The geometric surface processing unit is used to deform the geometric surface of the existing three-dimensional tree model and match it to the connecting component.