Rendering a non-photorealistic image

• US 6,593,924 B1
• Filed: 10/04/1999
• Issued: 07/15/2003
• Est. Priority Date: 10/04/1999
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Rosenzweig, Michael S., Lake, Adam T., Marshall, Carl S.
• Primary Examiner(s): Padmanabhan, Mano
• Application Number:
  US09/410,947
• Time in Patent Office: 1,380 Days
• Field of Search: 345/420, 345/423, 345/421, 345/426, 345/589
• US Class Current: 345/426
• CPC Class Codes: G06T 15/02 Non-photorealistic rendering
• CPC Class Codes: G06T 15/80 Shading

Abstract

A non-photorealistic image is rendered from an original model in a process which includes selecting a normal in the original model, selecting a vector from a set of vectors, and substituting the vector for the normal to produce a non-photorealistic image corresponding to the original model. The vector may be selected from a subdivision surface that defines a set of vectors, or it may be selected from a set containing a vector pointing substantially toward a virtual light source and a parameterized vector pointing between the virtual light source and a virtual eyepoint.

Claims

1. A method for use in rendering a non-photorealistic image from an original model, comprising:

selecting a normal in the original model that is not within a predetermined range of a virtual light source that illuminates the original model;

defining a single vector connecting the virtual light source and a virtual eyepoint from which the original model is viewed;

selecting a parameterized vector that goes from a point on the original model that corresponds to the normal to a point on the single vector; and

substituting the parameterized vector for the normal to produce a non-photorealistic image corresponding to the original model.

2. The method of claim 1, further comprising selecting the vector from a set of vectors.

3. The method of claim 2, further comprising:

selecting a normal that is within the predetermined range of the virtual light source; and

substituting a light vector for the normal that points towards the virtual light source.

4. A method for use in rendering a non-photorealistic image from an original model having a normal, comprising:

obtaining a subdivision surface that defines a set of vectors;

determining a vector defined by the subdivision surface that is most similar to the normal;

substituting the vector for the normal in the original model; and

storing an index to the subdivision surface along with data for the original model, the index corresponding to the vector substituted for the normal.

5. The method of claim 4, wherein obtaining comprises:

selecting an initial surface; and

dividing the initial surface to obtain the subdivision surface.

6. A method for use in rendering a non-photorealistic image from an original model having a normal, comprising:

determining a location of a virtual light source relative to the original model;

substituting a light vector for the normal if the normal is within a range of the virtual light source; and

substituting a parameterized vector for the normal if the normal is not within the range of the virtual light source, the parameterized vector comprising a vector that goes from a point on the original model that corresponds to the normal to a point on a single vector from the virtual light source to a virtual eyepoint from which the original model is viewed.

7. The method of claim 6, further comprising:

determining a location of the virtual eyepoint relative to the original model.

8. The method of claim 7, further comprising receiving a parameter for use in defining coordinates of the parameterized vector.

9. The method of claim 7, further comprising leaving the normal unchanged if the normal points away from the virtual eyepoint.

10. An article comprising a computer-readable medium that stores instructions for use in rendering a non-photorealistic image of an original model, the instructions for causing a computer to:

select a normal in the original model that is not within a predetermined range of a virtual light source that illuminates the original model;

define a single vector connecting the virtual light source and a virtual eyepoint from which the original model is viewed;

select a parameterized vector that goes from a point on the original model that corresponds to the normal to a point on the single vector; and

substitute the parameterized vector for the normal to produce a non-photorealistic image corresponding to the original model.

11. The article of claim 10, further comprising instructions that cause the computer to select the parameterized vector based on an input parameter that corresponds to a location on the single vector.

12. The article of claim 11, further comprising instructions that cause the computer to:

select a normal that is within the predetermined range of the virtual light source; and

substitute a light vector for the normal that points towards the virtual light source.

13. An article comprising a computer-readable medium that stores instructions for use in rendering a non-photorealistic image of an original model having a normal, the instructions for causing a computer to:

obtain a subdivision surface that defines a set of vectors;

determine a vector defined by the subdivision surface that is most similar to the normal;

substitute the vector for the normal in the original model; and

store an index to the subdivision surface along with data for the original model, the index corresponding to the vector substituted for the normal.

14. The article of claim 13, wherein obtaining comprises:

selecting an initial surface; and

dividing the initial surface to obtain the subdivision surface.

15. An article comprising a computer-readable medium that stores instructions for use in rendering a non-photorealistic image of an original model having a normal, the instructions for causing a computer to:

determine a location of a virtual light source relative to the original model;

substitute a light vector for the normal if the normal is within a range of the virtual light source; and

substitute a parameterized vector for the normal if the normal is not within the range of the virtual light source, the parameterized vector comprising a vector that goes from a point on the original model that corresponds to the normal to a point on a single vector from the virtual light source to a virtual eyepoint from which the original model is viewed.

16. The article of claim 15, further comprising instructions that cause the computer to:

determine a location of the virtual eyepoint relative to the original model.

17. The article of claim 16, further comprising instructions that cause the computer to receive a parameter for use in defining coordinates of the parameterized vector.

18. The article of claim 16, further comprising instructions that cause the computer to leave the normal unchanged if the normal points away from the virtual eyepoint.

19. An apparatus for use in rendering a non-photorealistic image of an original model, comprising:

a memory which stores computer instructions; and

a processor which executes the computer instructions to (i) select a normal in the original model that is not within a predetermined range of a virtual light source that illuminates the original model, (ii) define a single vector connecting the virtual light source and a virtual eyepoint from which the original model is viewed, (iii) select a parameterized vector that goes from a point on the original model that corresponds to the normal to a point on the single vector, and (iv) substitute the parameterized vector for the normal to produce a non-photorealistic image corresponding to the original model.

20. The apparatus of claim 19, wherein the processor selects the parameterized vector based on an input parameter that corresponds to a location on the single vector.

21. The apparatus of claim 20, wherein the processor selects a normal that is within the predetermined range of the virtual light source and substitutes a light vector for the normal that points toward the virtual light source.

22. An apparatus for use in rendering a non-photorealistic image of an original model having a normal, comprising:

a memory which stores computer instructions; and

a processor which executes the computer instructions to (i) obtain a subdivision surface that defines a set of vectors, (ii) determine a vector defined by the subdivision surface that is most similar to the normal, (iii) substitute the vector for the normal in the original model, and (iv) store an index to the subdivision surface along with data for the original model, the index corresponding to the vector substituted for the normal.

23. The apparatus of claim 22, wherein obtaining comprises:

selecting an initial surface; and

dividing the initial surface to obtain the subdivision surface.

24. An apparatus for use in rendering a non-photorealistic image of an original model having a normal, comprising:

a memory which stores computer instructions; and

a processor which executes the computer instructions to (i) determine a location of a virtual light source relative to the original model, (ii) substitute a light vector for the normal if the normal is within a range of the virtual light source, and (iii) substitute a parameterized vector for the normal if the normal is not within the range of the virtual light source, the parameterized vector comprising a vector that goes from a point on the original model that corresponds to the normal to a point on a single vector from the virtual light source to a virtual eyepoint from which the original model is viewed.

25. The apparatus of claim 24, wherein the processor determines a location of the virtual eyepoint relative to the original model.

26. The apparatus of claim 25, wherein the processor receives a parameter for use in defining coordinates of the parameterized vector.

27. The apparatus of claim 25, wherein the processor leaves the normal unchanged if the normal points away from the virtual eyepoint.

28. A method for use in rendering non-photorealistic cartoon images from data for an original three-dimensional model, comprising:

positioning the three-dimensional model in a first position;

substituting vectors for normals in the data to produce a non-photorealistic cartoon image corresponding to a first position of the original three-dimensional model, at least one of the vectors comprising a parameterized vector that goes from a point on the three-dimensional model in the first position that corresponds to a normal to a point on a single vector from a virtual light source that illuminates the three-dimensional model to a virtual eyepoint from which the three-dimensional model is viewed;

positioning the three-dimensional model in a second position; and

substituting vectors for normals in the data to produce a non-photorealistic cartoon image corresponding to the second position of original three-dimensional model, at least one of the vectors comprising a parameterized vector that goes from a point on the three-dimensional model in the second position that corresponds to a normal to a point on the single vector from the virtual light source to the virtual eyepoint.

29. The method of claim 28, further comprising selecting the parameterized vectors for the normals, for each position of the three-dimensional model, based on input parameters that correspond to locations on the single vector.

30. The method of claim 29, wherein, if a normal is within the predetermined range of the virtual light source, the method further comprises substituting a light vector for the normal that points towards the virtual light source.