Parameterization of deformation and simulation of interaction

• US 8,988,419 B2
• Filed: 11/27/2001
• Issued: 03/24/2015
• Est. Priority Date: 11/27/2000
• Status: Active Grant

• Current Assignee: Dean Huang
• Original Assignee: Dean Huang
• Inventors: Huang, Ding
• Primary Examiner(s): BROOME, SAID A
• Application Number:
  US10/416,459
• Publication Number:
  US 20040095352A1
• Time in Patent Office: 4,865 Days
• Field of Search: None
• US Class Current: 345/419
• CPC Class Codes: G06T 13/40 of characters, e.g. humans, animals or virtual beings
• CPC Class Codes: G06T 17/005 Tree description, e.g. octree, quadtree
• CPC Class Codes: G06T 17/10 Constructive solid geometry [CSG] using solid primitives, e.g. cylinders, cubes
• CPC Class Codes: G06T 19/00 Manipulating 3D models or images for computer graphics

Abstract

A method of using parametrical representations in modeling and animation is disclosed. This method is built directly on the inherent properties of parametric curves. Parametric curves are constructed and associated with geometric models, while at the same time the properties are used to represent the underlying mechanism of deformation. This method includes the steps of building parametrical representations on a geometric model, associating vertices of the model with different ones of the parametrical representations to effect movement thereof, and animating movement of the vertices to simulate relative motion therebetween.

The invention discloses a method in which simulation of object interaction and object deformation can be integrated into a unified framework through skeletal trees. The method preprocesses a graphic object and segments the object into a number of contexts at surface slope and curvature discontinuities. Then, control points are generated to represent these contexts. Based on these control points, a skeletal tree of the object can be built. Assisted by spatial decomposition, the skeletal trees can be directly used in the simulation of object interaction.

Claims

1. A computerized method for using curves to construct and control a geometric model of at least one physical object for simulation, animation or visual communication by a computer, said method comprising the steps of:

(a) providing to the computer a geometric model representing a physical object, at least a portion of the topography of the surface of said physical object being controlled by an underlying muscle mechanism of deformation of said physical object;

(b) providing and locating at least one control curve in the model based on the topography of said model such that modification of at least a section of said control curve has an effect on the topography of the model that is geometrically analogous to the effect of movement of the underlying muscle mechanism of deformation has on the topography of the surface of said physical object;

(c) associating elements of said model with elements of said at least one control curve by the computer so that said curves control movement of said elements of said model;

(d) dynamically modifying said at least one curve so that said model is dynamically changed so as to simulate the effect of the movement of the underlying muscle mechanism of deformation on the topography of the surface of the object to move a particular point on said surface to a different location, wherein said modifying of said curves is integral to simulating movement in the model equivalent to movement due to the underlying muscle mechanism of deformation of the physical object; and

(e) displaying the dynamically changed model.

2. The method of claim 1 wherein said curves are initially determined by the structure and the mechanism of deformation of the object.

3. The method of claim 1 wherein the association of said elements of said model and said elements of said curves is predetermined by the underlying mechanism of deformation of the object.

4. The method of claim 1 wherein each said element of an area of said model is associated with a sample element of at least one curve such that said element of said model is controlled by said at least one sample element, said area corresponding to said portion of the topology of the shape of said physical object.

5. The method of claim 4 wherein said element of said model is associated with said sample element of said at least one curve through a spatial gradient of said element of said model, the association being established when said sample element and said gradient satisfy a predetermined geometrical condition.

6. The method of claim 5 wherein the direction of said spatial gradient is geometrically analogous to a movement direction in proximity to the location of said element of said model, said movement direction being caused by said underlying mechanism of deformation.

7. The method of claim 1 wherein any one of said elements of said model is associated with and controlled by at least one of said curves-so that any one of said elements of said model can be controlled by either one or a plurality of said curves.

8. The method of claim 1 wherein the modification of said curves is predetermined by an underlying mechanism of deformation of a muscle-of the physical object.

9. The method of claim 1 wherein said curves are parametric curves, whereby properties of the parametric curves are used to describe and simulate the underlying mechanism of deformation of the object.

10. The method of claim 9 wherein said parametric curves are Non-Uniform Rational B-Splines (NURBS) curves, said properties comprise the properties that describe the repositioning of control points of the NURBS curves, and the modification of weighing parameters of the NURBS curves, such that repositioning control points and changing weighing parameters can modify the NURBS curves, which in turn can modify said model.

11. The method of claim 9 wherein control points of said parametric curves are located with respect to the topography of said model including various portions of anatomy.

12. The method of claim 1 wherein control parameters of said curves are set to different sets of values so that each set of the values produces a different shape of said model.

13. The method of claim 12 wherein locations of said curves are subject to an interpolative process so that any additional shape of said model is produced.

14. The method of claim 1 wherein;

the physical object is substantially an entire face;

the underlying muscle mechanism of deformation is underlying facial muscles;

the at least one control curve is at least one Non-Uniform Rational B-Spline (NURBS) parametric curve and modification of parameters of at least a section of said NURBS curve has an effect on the topography of the model that is geometrically analogous to the effect the movement of the underlying facial muscles has on the topography of the surface of the face, said curves being such that repositioning of control points of the NURBS curves and/or modification of weighing parameters of the NURBS curves provide said modification of parameters of the NURBS curves;

dynamically modifying said at least one curve is achieved by modifying parameters of the curve such that the effect generated in said model of the face is dynamically changed in the same way a face would change due to movement of underlying facial muscles so as to simulate the deformation of the face; and

wherein said modifying of said parameters of the curves is integral to simulating movement in the model of the face in the form of movement of a particular point on the surface of the face to a different location, which is equivalent to movement due to the mechanism of deformation caused by underlying facial muscles.

15. The method of claim 14 wherein the physical object has an underlying linear muscle and movement of the linear muscle is simulated in the model by changing the weight of one control point of the curve.

16. The method of claim 14 wherein the physical object has an underlying sphincter muscle and movement of the sphincter muscle is simulated in the model by updating the weights of several neighboring control points of the curve.

17. The method of claim 14 wherein the physical object has an underlying sheet muscle and movement of the sheet muscle is simulated in the model by updating the weights of several neighboring control points of the curve.