Scale separation in hair dynamics

Patent metadata

Field	Value
Publication number	US-9098944-B2
Application number	US-71754010-A
Country	US
Kind code	B2
Filing date	Mar 4, 2010
Priority date	Mar 4, 2010
Publication date	Aug 4, 2015
Grant date	Aug 4, 2015

Abstract

Techniques are disclosed for accounting for features of computer-generated dynamic or simulation models being at different scales. Some examples of dynamic or simulation models may include models representing hair, fur, strings, vines, tails, or the like. In various embodiments, features at different scales in a complex dynamic or simulation model can be treated differently when rendered and/or simulated.

First claim

What is claimed is:

1. A method comprising:
receiving, at a computer system, information specifying a first pose of a curve model, the curve model having a plurality of properties arranged along the curve model that each define how a simulator positions at least a portion of the curve model in response to one or more forces represented by the property;
receiving, at the computer system, information specifying a second pose of the curve model;
determining, with a processor associated with the computer system, a difference between the first pose of the curve model and the second pose of the curve model;
identifying, with the processor associated with the computer system, how one or more properties in the plurality of properties of the curve model contribute at their respective portions of the curve model to the determined difference;
grouping, with the processor associated with the computer system, each of the plurality of properties of the curve model into a plurality of scale separations, each scale separation categorizing a different manner in which a grouped property contributes at its corresponding portion of the curve model to the determined difference;
weighting, with the processor associated with the computer system, each of the plurality of scale separations grouping properties that influence position of their respective portions of the curve model in a similar manner with one or more assigned weights that indicate how much of the manner of which the one or more properties of the scale separation influence their respective properties is applicable at the corresponding scale separation; and
storing information describing the weighted plurality of scale separations in a storage device associated with the computer system.

2. The method of claim 1 wherein identifying how the one or more properties in the plurality of properties of the curve model contribute at their respective portions of the curve model to the determined difference comprises decomposing the determined difference using one or more filtering operations.

3. The method of claim 1 wherein identifying how the one or more properties in the plurality of properties of the curve model contribute at their respective portions of the curve model to the determined difference comprises decomposing the determined difference into one or more sets of properties configured differently as dynamic properties or properties used for simulation.

4. The method of claim 1 further comprising determining, with the processor associated with the computer system, one or more forces based on the weighted plurality of scale separations that move the second pose of the curve model toward the first pose of the curve model.

5. The method of claim 1 further comprising applying, with the processor associated with the computer system, one or more forces influenced by the weighted plurality of scale separations to move the second pose of the curve model toward the first pose of the curve model.

6. The method of claim 1 wherein the curve model represents hair.

7. A non-transitory computer-readable medium storing code configured to direct one or more processors associated with one or more computer systems, the non-transitory computer-readable medium comprising:
code for receiving information specifying a first pose of a curve model, the curve model having a plurality of properties that each define position of at least a portion of the curve model;
code for receiving information specifying a second pose of the curve model;
code for determining a difference between the first pose of the curve model and the second pose of the curve model;
code for identifying how one or more properties in the plurality of properties of the curve model contribute at their respective portions of the curve model to the determined difference;
code for grouping each of the plurality of properties of the curve model into a plurality of scale separations, each scale separation categorizing a different manner in which a grouped property contributes at its corresponding portion of the curve model to the determined difference;
code for weighting each of the plurality of scale separations grouping properties that influence position of their respective portions of the curve model in a similar manner with one or more assigned weights that indicate how much of the manner of which the one or more properties of the scale separation influence their respective properties is applicable at the corresponding scale separation; and
code for storing information describing the weighted plurality of scale separations.

8. The non-transitory computer-readable medium of claim 7 wherein the code for identifying how the one or more properties in the plurality of properties of the curve model contribute at their respective portions of the curve model to the determined difference comprises code for decomposing the determined difference using one or more filtering operations.

9. The non-transitory computer-readable medium of claim 7 wherein the code for identifying how the one or more properties in the plurality of properties of the curve model contribute at their respective portions of the curve model to the determined difference comprises code for decomposing the determined difference into one or more sets of properties configured differently as dynamic properties or properties used for simulation.

10. The non-transitory computer-readable medium of claim 7 further comprising code for determining one or more forces based on the weighted plurality of scale separations that move the second pose of the curve model toward the first pose of the curve model.

11. The non-transitory computer-readable medium of claim 7 further comprising code for applying one or more forces influenced by the weighted plurality of scale separations to move the second pose of the curve model toward the first pose of the curve model.

12. The non-transitory computer-readable medium of claim 7 wherein the curve model represents hair.

13. A non-transitory computer-readable medium storing computer-executable code configured to direct one or more processors associated with one or more computer systems, the non-transitory computer-readable medium comprising:
code for receiving information specifying a computer-generated character model having a plurality of material properties configured to be used by a simulator to determine motion and position of at least one or more portions of the model;
code for determining a difference between first pose information associated with the model and second pose information associated with the model, the second pose information received in response to input provided by one or more animators;
code for designating a first set of one or more of the plurality of material properties as fine properties based on how each material property in the first set contributes to the determined difference;
code for designating a second set of one or more of the plurality of material properties as coarse properties based on how each material property in the second set contributes to the determined difference;
code for receiving information weighting those properties designated as fine properties in a first manner and those properties designated as coarse properties in a second manner; and
code for generating third pose information for the model in response to applying a result of the simulator using the first pose information to the second pose information based on the weighting in the first manner of those properties designed as fine properties and the weighting in the second manner of those properties designated as coarse properties.

14. The non-transitory

Assignees

• Witkin Andrew P
• Anderson John
• Petrovic Lena
• Pixar

Inventors

• Witkin Andrew P
• Anderson John
• Petrovic Lena

Classifications

• G06T11/23

  using straight lines or curves · CPC title

• G06T2219/2016

  Rotation, translation, scaling · CPC title

• G06T2210/21

  Collision detection, intersection · CPC title

• G06T17/00

  Three-dimensional [3D] modelling for computer graphics · CPC title

• G06T19/00

  Manipulating three-dimensional [3D] models or images for computer graphics · CPC title