Three-dimensional paint projection weighting of diffuse and scattered illumination methods and apparatus

• US 7,176,918 B2
• Filed: 03/18/2005
• Issued: 02/13/2007
• Est. Priority Date: 04/30/2003
• Status: Active Grant

• Current Assignee: Pixar (The Walt Disney Company)
• Original Assignee: Pixar (The Walt Disney Company)
• Inventors: Anderson, John R., Kraemer, Manuel
• Primary Examiner(s): Zimmerman; Mark
• Assistant Examiner(s): Santiago; Enrique L.
• Application Number:
  US11/084,211
• Publication Number:
  US 20050179687A1
• Time in Patent Office: 697 Days
• US Class Current: 345/426
• CPC Class Codes: G06T 15/00 3D [Three Dimensional] image rendering
• CPC Class Codes: G06T 15/04 Texture mapping
• CPC Class Codes: G06T 15/10 Geometric effects
• CPC Class Codes: G06T 15/20 Perspective computation
• CPC Class Codes: G06T 15/50 Lighting effects
• CPC Class Codes: G06T 15/506 Illumination models
• CPC Class Codes: G06T 15/60 Shadow generation
• CPC Class Codes: G06T 15/80 Shading
• CPC Class Codes: G06T 17/00 Three dimensional [3D] modelling, e.g. data description of 3D objects
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607

Abstract

Methods for rendering an object includes determining diffuse illumination values for object surface points, associating a 3D grid including vertices with the object, mapping object surface points to vertices, determining diffuse illumination values for vertices from the diffuse illumination values for object surface points, low pass filtering diffuse illumination values for the vertices to determine illumination compensation values for the vertices, determining illumination compensation values for the object surface points from the illumination compensation values for the vertices, and determining compensated diffuse illumination values for the object surface points from a weighted combination of the diffuse illumination values and illumination compensation values for the surface points.

Claims

1. A method for rendering an object comprises:

determining diffuse illumination values for surface points on the object;

associating a three-dimensional grid with the object, wherein the three-dimensional grid includes a plurality of vertices, wherein the plurality of vertices define a plurality of voxels, and wherein each voxel includes at least a portion of the object;

mapping surface points on the object to a plurality of voxels;

determining diffuse illumination values for the plurality of vertices from the plurality of voxels in response to the diffuse illumination values for the surface points on the object,

performing one or more low pass filter operations on the diffuse illumination values for the plurality of vertices to determine diffuse illumination compensation values for the plurality of vertices;

determining diffuse illumination compensation values for the surface points in response to the diffuse illumination compensation values for the plurality of vertices;

determining compensated diffuse illumination values for the surface points on the object in response to a weighted combination of the diffuse illumination values for the surface points and the diffuse illumination compensation values for the surface points and

displaying an image on a display, wherein the image includes an appearance of at least a portion of the object determined in response to at least some of the compensated diffuse illumination values for the surface points.

2. The method of claim 1 wherein determining the compensated diffuse illumination values for the surface points on the object comprises:

determining weighting factors associated with each of the surface points; and

determining the compensated diffuse illumination values for the surface points on the object in response to the diffuse illumination values for the surface points, in response to the diffuse illumination compensation values for the surface points, and in response to the weighting factors associated with the surface points, respectively.

3. The method of claim 2 wherein determining the compensated diffuse illumination values for the surface points on the object comprises performing a weighted combination of the diffuse illumination values for the surface points and diffuse illumination compensation values for the surface points, in response to the weighting factors associated with the surface point.

4. The method of claim 2 wherein the weighting factors associated with each of the surface points is determined in response to input from a user.

5. The method of claim 4 wherein the weighting factors associated with each of the surface points is determined using two-dimensional paint projection techniques.

6. The method of claim 2 wherein a first set of surface points on the object at locations of finer geometric features are associated with smaller weighting factors compared to weighting factors of a second set surface points on the object at locations of coarser geometric features.

7. The method of claim 6

wherein at a surface point in the first set of surface points on the object at locations of finer geometric features, a diffuse illumination value and a diffuse illumination compensation values are combined in a first proportion;

wherein at a surface point in the second set of surface points on the object at locations of coarser geometric features, a diffuse illumination value and a diffuse illumination compensation values are combined in a second proportion; and

wherein the first proportion is larger than the second proportion.

8. The method of claim 2 further comprising:

determining an image in response to the compensated diffuse illumination values for the surface points; and

storing the image.

9. An image rendered according to the method described in claim 8.

10. An computer system comprises:

a memory configured to store a geometric description of an object;

a processor coupled to the memory, wherein the processor is configured to determine diffuse illumination values for surface points on the object, wherein the processor is configured to associate a three-dimensional grid comprising vertices and voxels with the object, wherein the processor is configured to map the surface points on the object to the voxels;

wherein the processor is configured to determine diffuse illumination values associated with the vertices in response to diffuse illumination values associated with the surface points, wherein the processor is configured to perform one or more low pass filtering operations on the diffuse illumination values associated with the vertices to determine compensation values for the plurality of vertices, wherein the processor is configured to determine compensation values for the surface points in response to the compensation values for the plurality of vertices, and wherein the processor is configured to determine compensated diffuse illumination values for the surface points on the object in response to a weighted combination of the diffuse illumination values for the surface points and the compensation values for the surface points.

11. The computer system of claim 10

wherein the processor is configured to determine weighting factors associated with each of the surface points;

and

wherein the processor is configured to determine the compensated diffuse illumination values for the surface points on the object in response to the diffuse illumination values for the surface points, in response to the compensation values for the surface points, and in response to the weighting factors associated with each of the surface points, respectively.

12. The computer system of claim 11

wherein the processor is configured to perform a weighted combination of the diffuse illumination values for the surface points and the compensation values for each of the surface points, in response to the weighting factors associated with the surface points.

13. The computer system of claim 11 wherein the processor is also configured to determine the weighting factors associated with each of the surface points in response to a two-dimensional image.

14. The computer system of claim 11

wherein the processor is configured to determine locations on the object having high-detail geometric features, and to determine locations on the object having low-detail geometric features.

15. The computer system of claim 14

wherein a first surface point on the object at a location having high-detail geometric features is associated with a first weighting factor;

wherein a second surface point on the object at a location having low-detail geometric features is associated with a second weighting factor; and

wherein the second weighting factor is greater than the first weighting factor.

16. A computer program product for a computer system including a processor comprises:

code that directs the processor to determine illumination values for surface positions on an object;

code that directs the processor to associate a three-dimensional grid including vertices and voxels with the object, wherein the surface positions on the object are within a plurality of voxels;

code that directs the processor to determine illumination values for a plurality of vertices associated with the plurality of voxels in response to the illumination values for the surface positions on the object;

code that directs the processor to perform a plurality of directional low pass filtering operations on the illumination values for the plurality of vertices to determine compensation values for the plurality of vertices;

code that directs the processor to determine compensation values for the surface positions on the object in response to the compensation values for the plurality of vertices;

code that directs the processor to form a weighted combination of the illumination values for the surface positions and the compensation values for the surface positions; and

code that directs a processor to display an image on a display, wherein the image includes an appearance of at least apportion of the object determined in response to at least some compensation values for the surface positions;

wherein the codes reside on a computer readable tangible media.

17. The computer program product of claim 16 wherein code that directs the processor to form a weighted combination of the illumination values for the surface positions and the compensation values for the surface positions comprises code that directs the processor to form a weighted combination of the illumination values for the surface positions and the compensation values for the surface positions, in response to weighting values for the surface positions.

18. The computer program product of claim 17 wherein the surface positions are associated with a single weighting value.

19. The computer program product of claim 17

wherein a first surface position is associated with a first weighting value;

wherein a second surface position is associated with a second weighting value; and

wherein the first weighting value and the second weighting value are selected from the group consisting of;

same, different.

20. The computer program product of claim 17 further comprising code that directs the processor to determine the weighting values for the surface positions in response to a three-dimensional paint-projected image.

21. The computer program product of claim 17 wherein the weighting values for the surface positions are determined in response to user input.

22. The computer program product claim 17 further comprising:

code that directs the processor to determine a first surface region of the object having a higher geometric complexity;

code that directs the processor to determine a second surface region of the object having a lower geometric complexity;

code that directs the processor to determine a first weighting value for the first surface region; and

code that directs the processor to determine a second weighting value for the second surface region;

wherein the first weighting value and the second weighting value are different.