System and Method for Simulating Shallow Water Effects on Arbitrary Surfaces

• US 20080177519A1
• Filed: 01/22/2008
• Published: 07/24/2008
• Est. Priority Date: 01/23/2007
• Status: Active Grant

• Current Assignee: Adobe Inc.
• Original Assignee: Adobe Systems Incorporated (Adobe Inc.)
• Inventors: Miller, Gavin S. P., Wang, Huamin
• Granted Patent: US 7,921,003 B2
• Time in Patent Office: Days
• US Class Current: 703/9
• CPC Class Codes: G06T 13/60 of natural phenomena, e.g. rain, snow, water or plants
• CPC Class Codes: G06T 2210/24 Fluid dynamics

Abstract

A system and method for shallow water simulation may provide a framework for solving General Shallow Wave Equations (GSWE) to efficiently simulate 3D fluid effects on arbitrary surfaces using a height field representation. The height field representation may include height columns constructed along surface normals, which may be dependent on a condition of boundary cells adjacent to fluid cells and/or artificial viscosity effects. The framework may provide implicit schemes for solving for the effects of external forces applied to the fluid, including gravity and surface tension, and explicit schemes for solving for advection effects. The system and method may be implemented on general-purpose CPU(s) and/or GPU(s) and may be capable of simulating a variety of fluid effects including: waves, rivulets and streams, drops, and capillary events. In some embodiments, the system and method may achieve real-time fluid control and fluid shape design through user-interaction (e.g., in a graphical painting application).

Claims

1. A system, comprising:

one or more processors; and

a memory coupled to the one or more processors and storing program instructions executable by the one or more processors to implement a shallow water simulator;

wherein the shallow water simulator is configured to simulate a three-dimensional fluid effect on a surface using a height field representation comprising height columns normal to the surface;

wherein the shallow water simulator is further configured to construct one or more of the height columns normal to the surface in a direction other than that of a gravity field for the three-dimensional fluid effect.

2. The system as recited in claim 1, wherein to simulate the three-dimensional fluid effect, the shallow water simulator is configured to solve a set of shallow wave equations restricted to two dimensions.

3. The system as recited in claim 1, wherein to simulate the three-dimensional fluid effect, the shallow water simulator is configured to solve for one or more external forces applied to the three-dimensional fluid effect, wherein the one or more external forces include one or more of:

gravity and surface tension.

4. The system as recited in claim 3, wherein to solve for the one or more external forces, the shallow water simulator is configured to solve for the one or more external forces using an implicit scheme.

5. The system as recited in claim 3, wherein to solve for the one or more external forces, the shallow water simulator is configured to separate at least one of the one or more external forces into a pressure component and an acceleration component, and to solve for effects of both the pressure component and the acceleration component on the three-dimensional fluid effect.

6. The system as recited in claim 5, wherein the one or more external forces comprise gravity, and wherein to solve for the one or more external forces, the shallow water simulator is further configured to apply a different value for a gravity acceleration component at each position of the three-dimensional fluid effect.

7. The system as recited in claim 5, wherein the shallow water simulator is configured to solve for the effects of the acceleration component using an explicit scheme to solve for height field advection.

8. The system as recited in claim 3, wherein the one or more external forces comprise surface tension, and wherein to solve for the one or more external forces, the shallow water simulator is further configured to apply surface tension pressures to both fluid cells and boundary cells of the three-dimensional fluid effect.

9. The system as recited in claim 3, wherein the one or more external forces comprise surface tension, and wherein to solve for the one or more external forces, the shallow water simulator is further configured to use a virtual surface method dependent on a contact angle at a boundary between the fluid and the surface.

10. The system as recited in claim 1, wherein the height field representation is dependent on a condition of boundary cells immediately adjacent to fluid cells.

11. The system as recited in claim 1, wherein the shallow water simulator is further configured to construct the height columns dependent on an artificial viscosity effect.

12. The system as recited in claim 1, wherein the shallow water simulator is further configured to generate image data for displaying the three-dimensional fluid effect.

13. The system as recited in claim 12, wherein the shallow water simulator is configured to generate the image data for displaying the three-dimensional fluid effect in real time.

14. The system as recited in claim 12, wherein the shallow water simulator is configured to generate the image data for displaying the three-dimensional fluid effect in response to interactive user control of the three-dimensional fluid effect.

15. The system as recited in claim 1, wherein the three-dimensional fluid effect includes one or more of:

waves, rivulets, streams, drops, and capillary events.

16. The system as recited in claim 1, wherein the one or more processors comprise at least one of:

a general- purpose central processing unit (CPU) and a graphics processing unit (GPU).

17. A computer-readable storage medium, comprising program instructions computer-executable to implement a shallow water simulator configured to simulate a three-dimensional fluid effect on a surface;

wherein to simulate the three-dimensional fluid effect, the shallow water simulator is configured to solve for one or more external forces applied to the three-dimensional fluid effect, wherein the one or more external forces include one or more of;

gravity and surface tension.

18. The storage medium as recited in claim 17, wherein to solve for the one or more external forces, the shallow water simulator is configured to solve for the one or more external forces using an implicit scheme.

19. The storage medium as recited in claim 17, wherein to solve for the one or more external forces, the shallow water simulator is configured to separate at least one of the one or more external forces into a pressure component and an acceleration component, and to solve for effects of both the pressure component and the acceleration component on the three-dimensional fluid effect.

20. The storage medium as recited in claim 17, wherein to simulate the three-dimensional fluid effect, the shallow water simulator is further configured to construct a height field representation comprising height columns normal to the surface, wherein one or more of the height columns normal to the surface is in a direction other than that of a gravity field for the three-dimensional fluid effect.

21. The storage medium as recited in claim 20, wherein the height field representation is dependent on one or more of:

a condition of boundary cells immediately adjacent to fluid cells and an artificial viscosity effect.

22. The storage medium as recited in claim 17, wherein to simulate the three-dimensional fluid effect, the shallow water simulator is configured to solve a set of shallow wave equations restricted to two dimensions.

23. The storage medium as recited in claim 17, wherein the shallow water simulator is further configured to generate image data for displaying the three-dimensional fluid effect.

24. The storage medium as recited in claim 23, wherein the shallow water simulator is configured to generate the image data for displaying the three-dimensional fluid effect in response to interactive user control of the three-dimensional fluid effect.

25. A computer-implemented method for simulating a three-dimensional fluid effect on a surface, comprising:

constructing a height field representation comprising height columns normal to the surface, wherein one or more of the height columns normal to the surface is constructed in a direction other than that of a gravity field for the three-dimensional fluid effect; and

generating image data for displaying the three-dimensional fluid effect.

26. The method as recited in claim 25, further comprising solving a set of shallow wave equations restricted to two-dimensions to simulate the three-dimensional fluid effect.

27. The method as recited in claim 25, further comprising solving for one or more external forces applied to the three-dimensional fluid effect, wherein the one or more external forces include one or more of:

gravity and surface tension.

28. The method as recited in claim 27, wherein said solving for one or more external forces, comprises solving for the one or more external forces using an implicit scheme.

29. The method as recited in claim 27, wherein said solving for one or more external forces, comprises:

separating at least one of the one or more external forces into a pressure component and an acceleration component; and

solving for effects of both the pressure component and the acceleration component on the three-dimensional fluid effect.

30. The method as recited in claim 25, wherein the height field representation is dependent on one or more of:

a condition of boundary cells immediately adjacent to fluid cells and an artificial viscosity effect.

31. The method as recited in claim 25, further comprising receiving user input for interactive control of the three-dimensional fluid effect;

wherein said generating image data for displaying the three-dimensional fluid effect is performed in response to said receiving.