JPH08221599A - Method for generating and analyzing three-dimensional motion - Google Patents

Abstract

PURPOSE: To spontaneously generate a skin corresponding to its attitude by raiding skeleton structure from motion captured data in the case of modeling the motion of a complicated structure. CONSTITUTION: This method is composed of an attitude analyzing part 3 for calculating the attitude of skeleton structure from a joint structure defining part 2 for defining human joint structure and a joint position designating part 1 for setting the positions of respective joints in that skeleton structure, dynamics analyzing part 4 for performing the calculation of dynamics, and skin generating part 5 for performing simplified modeling to the attitude of skeleton analyzed by the attitude analyzing part 3 and the dynamics analyzing part 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generates or analyzes natural motion data of humans or other complicated shapes (hierarchical structure) such as arms and legs in the field of computer graphics (CG) and various video production fields. For a three-dimensional motion generation method.

[0002]

2. Description of the Related Art Recently, TV commercials and game machines have been attracting attention as fields of use of CG. Conventional CG has generally been focused on creating a still image over time due to the limitation of calculation time. However, with the improvement of hardware and software technology in recent years, especially in the game market, C
G animation is receiving attention. In these fields, quick or natural movement is required for the characters and animals that appear.

Conventionally, animation generation for TV and movies has been
The method called the key frame method occupies the mainstream, and this method is basically used also in the above-mentioned CG animation production. Here, the key frame method will be described. The movement of the appearing character at time t0 of interest in the time axis direction is created. Then, the motion of the same character at a certain time interval t1 is created and saved. This is set for the required key frame in the time axis direction. When an animation is actually reproduced, the motion of each character in the above-mentioned key frames is interpolated (linear or spline) to compensate for the motion in the missing frames between the key frames to make a continuous animation.

Generally, the movement of a CG character includes a global movement that represents a locus of arrangement and movement in a three-dimensional space and a local movement such as a walking movement and a movement regardless of the arrangement. Among these, the former can set the key position in the three-dimensional space by the key frame method described above, and then interpolate between them to specify the movement, but when the arm descends in the golf swing, It is difficult to easily and naturally set foot movements during walking by the key frame method alone.

On the other hand, in recent years, a method called motion capture has begun to be used when modeling a local motion of a human being or the like. This defines motion by attaching sensors to the main parts of the human body (tens of points such as joints and head) that are the model, and making the model perform the necessary motion. In addition, it is a method that can measure a three-dimensional coordinate of a main part of human motion at a certain time interval using a detector of a camera or a sensor, and use the data to model a local motion. Optical and magnetic sensors have been developed due to the different types of sensors.

[0006]

However, it is difficult for the conventional key frame method to smoothly and faithfully model the local movement of a complex structure such as a human. Also, in modeling human motion using the motion capture method, etc., when modeling a motion in which the trajectory of the arm is slightly different even if the person changes or the motion is almost the same, There is a problem that it takes time and effort for modeling because it requires a new exercise. In view of the above problems, the present invention provides a three-dimensional motion generation method capable of efficiently modeling a three-dimensional motion of a complicated structure such as a human and analyzing the motion according to a dynamic model. With the goal.

[0007]

In order to solve the above problems, in the three-dimensional motion generation method of the present invention, a skeleton structure called a skeleton is defined and given to define a complex structure such as a human being. A mechanism for assigning the skeletal structure to the character is provided. In addition, the skin that includes the skeleton is added to the coordinate position of the skeleton that is obtained from the mechanism that allocates the volume that includes each part of the skeletal structure and calculates the dynamics and the analysis result. And a mechanism that reproduces the swelling of muscles such as arms according to the movement of the skeleton.

[0008]

With the above-described structure, the present invention can quantitatively analyze a motion in consideration of dynamic characteristics when modeling a motion such as an arm or a foot of a character having a complicated structure such as a human being, and a skeleton. It is possible to newly create or change a motion that matches the actual motion from the analysis of the position by the structure. Further, by generating a flexible skin (flexible skin) surrounding the skeleton for the analyzed result, it is possible to generate and visualize some movement between solids.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A three-dimensional motion generating method and apparatus according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a three-dimensional motion generation method and apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a joint position designation unit, 2 is a joint structure definition unit, 3 is a posture analysis unit,
Reference numeral 4 is a dynamic analysis unit, and 5 is a skin generation unit. The operation of the three-dimensional motion generation method and apparatus configured as described above will be described below with reference to FIG.

First, in the joint position designation unit 1, a complex structure such as a human is defined by a joint structure called a skeleton (see FIG. 3), and the three-dimensional coordinate position of the joint (also called a joint) or joint angle information. The time change amount of (direction) is given as time series data. The joint in Figure 2 (Hipp
An example of joint data of s) is shown. The data includes the name of the link (Segment) and the number of previous frames, the frame rate (30 frames per second in the example), and the position (Xtran, Ytran, Ztran) of the joint in the absolute coordinate system, and the angle (Xrot, Yrot, Zro).
t) and scale (Xscale, Yscale, Zscale) data are given as a time series for the number of frames. Generally, this data itself uses a motion capture system etc.
A sensor (magnetism, optical tape, etc.) is attached to a main joint position of a model human to move the model, and it can be obtained from three-dimensional trajectory information of the sensor position.

Next, the joint structure defining section 2 defines a skeleton structure. Figure 3 shows the standard human skeleton structure and the names of each part. FIG. 3A shows the entire skeleton structure. In FIG. 3A, P1, P2 ... Pn are joints, and the straight line connecting them is called a link (or segment). Further, FIG. 7B and FIG. 7C are parts of FIG. In the skeleton structure of FIG. 3, what is required is the parent-child relationship of each link and the positional relationship of each joint,
The structure shown in FIG. 4 is used as the data structure for analysis due to the degree of freedom of rotation and the limitation of the rotation angle. The joint structure defining unit 2 expresses the structure of the skeleton to be analyzed from now on by the structure shown in FIG. 3 and holds it in the internal memory with the internal data structure shown in FIG.

The posture analysis unit 3 analyzes the skeleton posture (kinematics) using the internal analysis data structure (see FIG. 4) defined by the joint structure definition unit 2. Next, a basic posture analysis method will be described. Attitude analysis uses the method conventionally used for attitude control of robot arms. In an open-loop linear link structure represented by joints and links as shown in Fig. 3, the joint that serves as the reference of analysis is called the base, and the origin of the coordinate system for analysis is used as the base (the coordinate system will be referred to as the right-hand system hereafter). ,),
On the contrary, the end point of analysis (generally the tip of the arm) is called an effector. The information required for attitude control is the parent-child relationship of links, the initial position of the skeleton structure, the degree of freedom of rotation of each joint, and the limitation of rotation (generally 3 degrees of freedom in the XYZ directions). For a certain skeleton structure, the temporal change of the trajectory of the effector part (maximum, translation 3 elements, rotation 3 elements 6
Inverse kinematics is the method to obtain the angle information of each joint when given the element), and conversely is the method to obtain the position of the effector when a minute time change of the angle of each joint is given. Call it Su. For more information on kinematics, see References: 1) Hirose, Robotics (Shokabo). 2) See Arimoto, Robot Dynamics and Control (Asakura Shoten).

Generally, there is a linear relationship between the angle information θi (t) of each joint of the skeleton structure shown in FIG. 3 (to be precise, a minute time change amount) and the minute change amount of the effector posture (maximum 6 variables). Yes, the proportional coefficient matrix is called the Jacobian matrix (the inverse relationship is the inverse Jacobian matrix). Regarding the forward kinematics, the Jacobian matrix is obtained by sequentially obtaining the link length and the rotation matrix of each joint from the skeleton structure shown in FIG. 3 in the posture analysis unit 3 of FIG. further,
By giving the time-series data (see FIG. 2) of the angle change of each joint from the joint position designation unit 1, the position of the effector at a certain time is uniquely determined using the Jacobian matrix. On the other hand, in inverse kinematics, the position of an arbitrary joint at each time can be obtained by mathematically obtaining the inverse Jacobian matrix and applying the posture of the effector given to the joint position designation unit to it.

In the conventional analysis link, for example, only the human arm and foot shown in FIG. 3 (simple linear link) can be analyzed. However, in the case of a complex structure such as a human being, a plurality of skeletons (for example, arm 2
It is necessary to connect two books and two legs), and further it is necessary to analyze kinematics across a plurality of skeletons (for example, from right hand to left hand). The kinematics analysis method when straddling a plurality of skeletons will be described below.

FIG. 5 shows an example of a skeleton in which the left and right arms of a human being are connected with the body sandwiched therebetween. In the structure shown in Fig. 5, when the analysis of the posture extending from the right arm to the left arm is required, the joint position with the body part is disconnected at the different position (A, B) of the Body segment, so the kinematic I can't analyze the ticks. Therefore, as shown in FIG. 5, consider a virtual link that connects the connection joint position A of the right arm and the connection position B of the left arm with a straight line (dashed line in the figure).
In addition, consider a virtual link that includes A and B (used for the dynamic analysis described below in the boundary box),
The normal kinematics calculation is performed with a single linear link connecting the right and left arms.

Next, the joint angle limitation of the joint in the posture control will be described. Generally, the maximum degree of freedom for rotation of each joint of skeleton structure is 3 (around XYZ axes)
Is. This is set by setting a local coordinate system at each joint position and rotating around each axis. When solving the skeleton structure with inverse kinematics (which is also necessary for forward kinematics), the degree of freedom and the angle of a joint may be set. This is set by the Type and Limit of Joint of the data structure shown in FIG. Type indicates which axis can be rotated,
Limit sets the angular range that can be rotated with respect to each rotation axis. Human arms and legs are generally targets for the torso, and the elbow joints of the left and right arms do not bend outside the body. By assigning to the entire skeleton structure, the angular range of each joint can be set automatically. The above parameters are created in advance as a data file in consideration of the skeleton structure.

In the dynamic analysis unit 4, an elliptic cylinder for analysis is considered for each link of the skeleton structure shown in FIG. FIG. 6 shows a cylinder for analysis assigned to the link. For the dynamic analysis, the shape of the cylinder (calculating the inertia tensor) and the position of the center of gravity,
Mass etc. are required. First, the inertia tensor of the link is calculated using the link for this analysis. The origin of the calculation is the coordinate system at the position of the joint near the root for each link. Furthermore, the torque acting on each joint of the skeleton structure shown in FIG. 3 can be calculated by calculating the sum of kinetic energy and potential energy of each link structure (referred to as Lagrangian) and differentiating Lagrangian with respect to time.

In general, the torque τ acting on a joint is
It can be expressed in a linear form of the angle change amounts (angular velocity and angular acceleration) θ′i and θ′′i of all joints located on the route from the joint. The above-mentioned inertia tensor is applied to each proportional constant (for details of the torque calculation formula, refer to Reference 2 in the previous art). In the dynamic analysis method, as in the case of the posture analysis, the angle change of each joint of the skeleton is given and the torque acting on the joint is calculated (reverse dynamics), and the change amount of the torque at the opposite time is calculated. There is a method of obtaining joint angle information (angular acceleration) (referred to as forward dynamics).

First, the inverse dynamic will be described below. As explained in the posture control, when analyzing the dynamics of a complicated skeleton structure as shown in Fig. 3, the skeleton units such as arms and legs are analyzed individually, and the results are used as the base body (Hips). To connect. Coordinate transformation matrix at each joint position of the skeleton found in attitude control (4 * consisting of link vector and rotation matrix)
4 homogeneous matrix) is used as internal data. Calculate the coordinate transformation matrix Ai (t} by the number of joints, and then calculate the first and second partial derivatives of Ai (t) with respect to each joint angle θi, and further calculate the inertia tensor of each link. .

The inertia tensor is uniquely determined from the shape and mass of the bottom surface and the length when an analysis link as shown in FIG. 6 is used. On the other hand, the angle information of each joint is given from the joint position designation unit 1 in time series as the angle change of each joint for each frame. Internally, by using the difference approximation from this time series data, the angular velocity is further calculated and the angular acceleration is calculated from the difference. The torque acting on an arbitrary joint at a certain time can be calculated from the angular velocity and the angular acceleration, the inertia tensor, and the angular derivative of the coordinate transformation matrix Ai (t). By repeating this process sequentially, the time change of torque can be calculated.

By using the above-mentioned dynamics calculation by using the time data of a human golf swing obtained by motion capture or the like, it is possible to calculate the torque characteristic acting on an arbitrary joint in a certain swing. In addition to this, it becomes possible to analyze movements more quantitatively.

Next, a method for analyzing forward dynamics will be described. The calculation procedure in the analysis process is the same as the inverse dynamics described above, but in the forward dynamics, it is necessary to give a change in torque to calculate the angle of each joint. When trying to solve this mathematically, it is necessary to solve a partial differential equation, but it is not possible to uniquely determine because there are more variables than there are equations. Therefore, a linear approximation calculation is used. The formula for calculating the torque can be expressed in the linear form of the first and second partial derivatives of the joint angle θi (t). Therefore, if the torque at a certain time t is given, the angular velocity θ'i (t) at the time t is
Difference approximation is performed using a data series of angular velocities up to t-1.
For example, linear interpolation may be performed from the angular velocity data at times t-2 and t-1. If the angular velocity at time t is obtained, the angular acceleration at time t can be uniquely determined from the above relational expression of torque. By repeating this operation sequentially over the time interval of the desired torque, the dynamics of the skeleton structure when the torque changes can be calculated.

[0023]

[Equation 1]

The above is the posture control method and the dynamic calculation method when the motion of each joint given by the joint position designation section is given to the analysis structure defined by the joint structure definition section 1.

Next, a method of generating a skin for human fleshing the motion of the skeleton structure obtained as described above will be described. In the embodiment of the present invention, a free-form surface (Bezier or Spline) consisting of a plurality of sets (2 or 4) is assigned to one skeleton link given by the joint structure defining unit 1. FIG. 7 shows a diagram in which two free-form curved surface skins are assigned to one link. In the figure, it is assumed that the link can rotate around the X axis. Two free-form surfaces (consisting of 25 control points per sheet) are arranged in the direction perpendicular to the axis of rotation, and the control points are arranged on the vertices of the truncated pyramid and on the sidelines of the sides as shown in the figure. . A method of deforming the joint portion with respect to the skin thus assigned will be described.

FIG. 8 shows an explanatory view of the deformation of the skin due to the bending of the joint. The figure (a) shows the state where the joint part is extended, and the figure (b) shows the state when the joint rotates by the angle θ. First, consider a virtual spherical surface centered on the joint at the joint portion. This sphere is the minimum circumscribing of the rectangle given by the boundary (a_up, B_up) of the upper link and the rectangle given by the boundary (a_down, b_down) of the lower link of the joint part, as shown in Fig. 7 (c). It is a sphere. When a joint bends, the common control point (P42, P02, etc.) of the skins of the upper arm and the lower arm is moved to a position on the sphere at the bisector of the angle of bend θ, to respond to the bend of the joint. Continuous skin deformation is possible.

FIG. 9 shows a method of deforming the boundary (pyramidal pyramid) of the skin shown in FIG. 7 when there is rotation (twisting component) in the longitudinal direction of the link. When the angle of twist is given, the upper base is rotated around the rotation axis connecting the centers of the upper base and the lower base, and the skin deformation control point is selected on the straight line connecting the respective vertices.

Finally, a method of converting the motion capture data into the movement amount of the joint structure will be described. The joint position designation unit 1 shown in FIG. 1 designates the amount of change of each joint of the skeleton defined by the joint structure definition unit 2. Generally, a motion of a complex structure such as a human being is created by a method called motion capture. This is to measure the position of the sensor when the sensor is attached to the joint position of the human model and the model is moved (such as golf swing). Finally, the data is the joint position information shown in FIG. Given as. The above-mentioned posture control and dynamic analysis mainly require the structure of the joint (initial state) and the amount of change in the angle of each joint in local coordinates. In order to calculate this amount of change in angle, it is necessary to perform data conversion from the position of the sensor described above to the joint position for analysis. A specific example will be described below. Generally, the three-dimensional coordinate measured by motion capture is the position of the sensor, which generally does not coincide with the joint position for analysis. FIG. 10 shows a general measurement position (a sensor position is a numbered point in the figure) and a joint for analysis when capturing a human motion.

What is required in this structure is a three-dimensional angle (rotation angle around the XYZ axes) at each joint (black circle in the figure). In order to obtain this, it is set as a vertex for the joint of interest (for example, 8 in the figure), and a point (10, 9) on the rotation axis (for example, 10, 9) of the next joint is set as a vertex at a triangular position Place the sensor. This triangle 8,
The outer product vector p as shown in FIG. Vector p and rotation axis vector (9, 10) are 8
3 in the joint 8 by finding how much each is rotating in the local coordinate system (XYZ) set at the position of
The rotation angle of freedom can be calculated.

[0030]

As described above, according to the present invention, when three-dimensional motion data of a complicated structure such as a human arm or foot is created, the human structure is defined by a skeleton structure and the joints are defined. By setting the restriction of the part, the human's natural posture can be set. In addition, it is possible to quantitatively analyze the motion by considering the volume for analysis including the skeleton and using it to perform the dynamic analysis. Furthermore, by allocating a plurality of skins corresponding to the above skeleton links and deforming the skins according to the bending of the joint, it is possible to generate and analyze a three-dimensional motion.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a three-dimensional motion generation device according to an embodiment of the present invention.

[Fig. 2] Time series data chart of joint

[Figure 3] Human skeleton structure diagram

FIG. 4 is an explanatory diagram of an internal data structure for analysis.

FIG. 5 is an explanatory diagram of posture analysis across a plurality of skeletons.

[Fig.6] Link structure diagram for dynamic analysis

FIG. 7 is an explanatory diagram of a skin generation method.

FIG. 8 is an explanatory diagram of skin deformation at a joint portion.

FIG. 9 is an explanatory diagram of skin deformation in a twisting direction at a joint portion.

FIG. 10 is an explanatory diagram of joints for measurement points and analysis in motion capture.

FIG. 11 is an explanatory diagram of how to determine the rotation angle of the joint.

[Explanation of symbols]

 1 joint position designation unit 2 joint structure definition unit 3 posture analysis unit 4 dynamics analysis unit 5 skin generation unit

Claims (9)

[Claims] 1. A joint structure defining section configured to link a complicated joint structure of a human or the like with a joint, and their position and connection relationship, and a constraint condition of movement at each joint, and the joint structure defining section. For each joint of the joint structure, a degree of freedom, a joint rotation angle according to the degree of freedom, a three-dimensional coordinate position and angle of the joint, and a joint position designating unit for limiting the rotation in time series; A posture analysis unit that obtains the position of a joint at any time from the joint structure given by the definition unit and the position information of each joint given by the joint position designation unit, and each link of the joint defined by the joint structure definition unit. On the other hand, in a three-dimensional motion generation device including a dynamic analysis unit that sets the center of mass and volume and calculates the dynamic characteristics of each link, the posture of the structure defined by the joint structure definition unit is determined. With respect to the method, a plurality of joint structures are connected to different positions of a base link that determines a relative position in a three-dimensional space, and the postures of the plurality of joint structures are sought over the base link. At this time, a virtual link that connects the joints serving as the starting points (roots) of the plurality of joint structures with a straight line is generated, the analysis priority is given to the link structure, and the plurality of joints and the virtual joint are set according to the priority order. Three-dimensional motion generation method characterized by performing posture analysis on a straight-chain link that straddles a dynamic link. 2. When obtaining the dynamic characteristics of the link which is the base of the joint structure under the condition described in claim 1, the volume and the center of mass as the mechanical constants necessary for the dynamic analysis are used as the base. A three-dimensional boundary shape including all root positions of a plurality of joint structures connected on the joint structure is obtained, and the volume and barycenter position of the virtual boundary are calculated as the volume of the mechanical constant for the dynamic analysis and It is characterized in that the dynamic characteristics of a linear link extending over the plurality of joint structures and the joint structure serving as the base are analyzed at the position of the center of gravity.
Dimensional motion analysis method. 3. A joint structure defining section configured by linking a complex joint structure of a human or the like with a joint, and a positional and connection relationship between them and a constraint condition of movement in the joint, and a joint defined by the joint structure defining section. For each joint in the structure, the degree of freedom and the rotation angle of the joint and the joint
A joint position designation unit that gives time series restrictions on the dimensional coordinate position, angle, and rotation, and a joint at an arbitrary time from the joint structure given by the joint structure definition unit and the position information of each joint given by the joint position designation unit. And a dynamics analysis unit that calculates the dynamic characteristics of each link by setting the center of mass and volume for each link of the joint defined by the joint structure definition unit. In a three-dimensional motion generation device, regarding a method of determining a posture of a structure defined by the joint structure definition unit, in consideration of the symmetry of an arm or a foot of an animal or the like, a right and left sides relative to a base joint structure serving as a torso In consideration of the positional relationship between the arms and legs, the joint structure that hits the left and right arms can be actually bent by limiting the joint rotation on the opposite side of the body. Not in the direction 3 dimensional motion generating method characterized by performing and attitude and dynamic analysis by adding a restriction of the rotation of the foot. 4. A joint structure defining section configured by linking a complicated joint structure of a human or the like with a joint, and a position and connection relationship between them and a constraint condition of movement in the joint, and a joint defined by the joint structure defining section. For each joint in the structure, the degree of freedom and the rotation angle of the joint and the joint
A joint position designation unit that gives time series restrictions on the dimensional coordinate position, angle, and rotation, and a joint at an arbitrary time from the joint structure given by the joint structure definition unit and the position information of each joint given by the joint position designation unit. And a dynamics analysis unit that calculates the dynamic characteristics of each link by setting the center of mass and volume for each link of the joint defined by the joint structure definition unit. In a three-dimensional motion generation device, regarding a motion analysis method of a joint structure analyzed by the dynamics analysis unit, regarding a joint structure of a human or the like given by the joint structure definition unit and each joint given by the joint position designation unit. The dynamic characteristics of the entire joint structure or a specified part of the joint structure is calculated using the time series of the angle change, and the time change of the angle at any time is calculated from the time change of the angle information of each joint. And the change in the amount of time change of the angle are calculated from the time series data of the angle, the inertia tensor of the link is obtained from the data and the physical shape of each link at a certain time, and the torque acting on any joint at a certain time. A three-dimensional motion generation method characterized in that the motion of a human being or the like is quantitatively analyzed by sequentially calculating from the above data. 5. A joint structure defining section configured by linking a complex joint structure of a human or the like with a joint, and a positional and connection relation between them and a constraint condition of movement in the joint, and a joint defined by the joint structure defining section. For each joint in the structure, the degree of freedom and the rotation angle of the joint and the joint
A joint position designation unit that gives time series restrictions on the dimensional coordinate position, angle, and rotation, and a joint at an arbitrary time from the joint structure given by the joint structure definition unit and the position information of each joint given by the joint position designation unit. And a dynamics analysis unit that calculates the dynamic characteristics of each link by setting the center of mass and volume for each link of the joint defined by the joint structure definition unit. In a three-dimensional motion generation device, when the amount of change in the torque acting on an arbitrary joint of the joint structure at a certain time is known, the time change of the amount of change in the angle (angular velocity) of the arbitrary joint at that time is calculated. Obtained by linear approximation from time series data of angle and time series data of angular velocity, using the value of the torque and the value of the angular velocity at a certain time, the time of the angular velocity at that time By obtaining reduction amount (angular acceleration),
A three-dimensional motion generation method characterized by analyzing a motion of a joint structure at an arbitrary time. 6. A joint structure defining section configured by linking a complicated joint structure of a human or the like with a joint, and a positional and connection relationship between them and a constraint condition of movement in the joint, and a joint defined by the joint structure defining section. For each joint in the structure, the degree of freedom and the rotation angle of the joint and the joint
A joint position designation unit that gives time series restrictions on the dimensional coordinate position, angle, and rotation, and a joint at an arbitrary time from the joint structure given by the joint structure definition unit and the position information of each joint given by the joint position designation unit. A posture analysis section for obtaining the position of the joint, a dynamics analysis section for calculating a dynamic characteristic for each link by setting a center of mass and a volume for each link of the joint defined by the joint structure definition section, and the joint A skin with a mechanism that assigns multiple free-form surfaces to each link of a joint structure such as a human being defined in the structure definition part, and moves the control points of the free-form surface according to the angle change of the joint. In a three-dimensional motion generation device including a generation unit,
Regarding how to determine the control point position of the free-form surface of the joint according to the change of the joint angle in the skin generation part, regarding the change and the side surface of the truncated pyramid including a plurality of free-form surfaces for each link, etc. Consider a virtual sphere that includes all the vertices of the bottom surface of the truncated pyramid in the joint part, and divides the control point of the free-form surface at the joint part into equal joint angles when the joint angle changes. A three-dimensional motion generation method characterized in that the position is taken on the virtual sphere. 7. A joint structure defining section configured by linking a complex joint structure of a human or the like with a joint, and a position and connection relationship between them and a constraint condition of movement in the joint, and a joint defined by the joint structure defining section. For each joint in the structure, the degree of freedom and the rotation angle of the joint and the joint
A joint position designation unit that gives time series restrictions on the dimensional coordinate position, angle, and rotation, and a joint at an arbitrary time from the joint structure given by the joint structure definition unit and the position information of each joint given by the joint position designation unit. A posture analysis section for obtaining the position of the joint, a dynamics analysis section for calculating a dynamic characteristic for each link by setting a center of mass and a volume for each link of the joint defined by the joint structure definition section, and the joint A skin with a mechanism that assigns multiple free-form surfaces to each link of a joint structure such as a human being defined in the structure definition part, and moves the control points of the free-form surface according to the angle change of the joint. In a three-dimensional motion generation device including a generation unit,
Regarding a method of deforming a skin by twisting a link in the skin generating part, consider a truncated pyramid that includes each link of the joint structure, and when an angle related to the twist of a target joint is given, the upper base of the truncated pyramid A three-dimensional motion generation method comprising rotating a quadrangle corresponding to a lower base at an angle relative to a quadrangle corresponding to a lower base, and arranging the control points of the free-form surface on the side and surface of the twist. 8. A joint structure definition unit configured to link a complicated joint structure of a human or the like with a joint, a position and connection relationship between them, and a constraint condition of movement at each joint, and the joint structure definition unit. For each joint of the joint structure, a degree of freedom, a joint rotation angle according to the degree of freedom, a three-dimensional coordinate position and angle of the joint, and a joint position designating unit for limiting the rotation in time series; A posture analysis unit that obtains the position of a joint at any time from the joint structure given by the definition unit and the position information of each joint given by the joint position designation unit, and each link of the joint defined by the joint structure definition unit. On the other hand, in a three-dimensional motion generation device including a dynamic analysis unit that sets the center of mass and volume and calculates the dynamic characteristics of each link, the angle change of each joint of the joint structure in the joint position designation unit Regarding the calculation method, in order to calculate the rotation angle of the three-dimensional coordinate system at each joint of the joint structure, consider a triangle with the target joint as the vertex and two other points on a straight line parallel to the rotation axis. , Using the cross product vector of two vectors dropped from the apex on the joint of interest to the other two points and the vector on the straight line connecting the other two points, in the XYZ directions at the joint of interest A three-dimensional motion generation method characterized by calculating a rotation angle. 9. A joint structure definition unit configured to link a complicated joint structure of a human or the like with a joint, a position and connection relationship between them, and a constraint condition of movement at each joint, and the joint structure definition unit. For each joint of the joint structure, a degree of freedom, a joint rotation angle according to the degree of freedom, a three-dimensional coordinate position and angle of the joint, and a joint position designating unit for limiting the rotation in time series; A posture analysis unit that obtains the position of a joint at any time from the joint structure given by the definition unit and the position information of each joint given by the joint position designation unit, and each link of the joint defined by the joint structure definition unit. On the other hand, in a three-dimensional motion generation device including a dynamic analysis unit that sets the center of mass and volume and calculates the dynamic characteristics of each link, the human motion is used as three-dimensional position or angle information of the joint. The imported data is converted into a structure for analysis in the joint position designation unit, set as a joint structure for analysis in the joint structure definition unit, and the structure is jointed in the posture analysis unit or the dynamics analysis unit. A three-dimensional motion analysis method characterized in that torque characteristics are calculated for each and the motions of a plurality of humans are compared with each other to quantitatively compare the motions.