Method and system for interactive simulation of materials

• US 8,395,626 B2
• Filed: 04/06/2007
• Issued: 03/12/2013
• Est. Priority Date: 04/08/2006
• Status: Active Grant

• Current Assignee: Alan Millman
• Original Assignee: Alan Millman
• Inventors: Millman, Alan
• Primary Examiner(s): Tung, Kee M
• Assistant Examiner(s): Liu, Zhengxi
• Application Number:
  US11/784,455
• Publication Number:
  US 20070239409A1
• Time in Patent Office: 2,167 Days
• Field of Search: 345473-475, 345/419, 434/262
• US Class Current: 345/473
• CPC Class Codes: G06F 2111/10 Numerical modelling
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30
• CPC Class Codes: G06F 30/23 using finite element methods [FEM] or finite difference methods [FDM]
• CPC Class Codes: G06T 13/00 Animation

Abstract

A method and system for interactive simulation of materials. The method and system provide flexible simulation, the ability to combine rigid and flexible simulation, a collision-detection method for simulating objects and other entities, and a system for displaying and interacting with simulated objects which includes a harness for registering the hardware components of the simulation with respect to each other.

Claims

1. A method for simulating rigid, semi-rigid, and flexible components of materials comprising:

(a) defining on a network device with one or more processors, one or more individual components for each of one or more entities being simulated, wherein a three-dimensional (3D) entity includes at least four individual components combined into the 3D entity being simulated;

(b) defining for each of the one or more individual components, a force transmission parameter obtained from a plurality of force transmission parameter values, such that a selected entity'"'"'s rigid mass is greater than zero and less than its total mass, the plurality of force transmission parameter values including a first force transmission parameter value representing a fully flexible component, a second force transmission parameter value representing a fully rigid component and a plurality of other force transmission parameter values with values in-between the first force transmission parameter value and the second force transmission parameter value representing varying levels of semi-rigidity, wherein the selected entity'"'"'s rigid mass is calculated according to the equation;

2. A non-transitory computer readable medium having stored therein instructions for causing the one or more processors to execute steps (a) through (g) of the method of claim 1.

3. The method of claim 1 wherein the composite simulation method includes a combination of a rigid-body method and a spring-and-dashpot method.

4. The method of claim 1 wherein the composite simulation method includes a combination of a rigid-body method and a finite-element method.

5. The method of claim 1 wherein the one or more individual components for each of one or more entities being simulated are simulated using a method for simulating flexible components including hookian springs.

6. The method of claim 1 wherein the one or more individual components for each of one or more entities being simulated are simulated using the method for simulating flexible entities including a method comprising a single type of orientation-preserving springs.

7. The method of claim 6 wherein any of the orientation-preserving springs'"'"' rest-vectors are changed over time.

8. The method of claim 1 wherein the one or more individual components for each of one or more entities being simulated are simulated using the method for simulating flexible entities including a method comprising one or more types of orientation-preserving springs.

9. The method of claim 8 wherein the one or more types of orientation-preserving springs include using different types of simulated orientation-preserving springs depending upon whether or not an orientation-preserving spring is internal or external to a single body portion or a plurality of body portions of an entity being simulated.

10. The method of claim 9 wherein internal orientation-preserving springs do not apply torques to a single body portion or a plurality of body portions of an entity being simulated.

11. The method of claim 8 wherein the one or more types of orientation-preserving springs are used for creating dynamic motion in an entity being simulated comprising:

using one or more orientation-preserving springs between components of the entity being simulated for creating dynamic motion; and

changing a rest-vector of one or more orientation-preserving springs over time.

12. The method of claim 11 wherein one or more rest-vectors of the one or more orientation-preserving springs are changed over time according to any of:

a) predetermined key-frame positions,

b) tables of data or functions residing in a computer database or memory,

c) response to user input, or a combination thereof.

13. The method of claim 8 further comprising:

using one or more orientation-preserving springs between components of an entity being simulated; and

modifying a rest-vector of one or more orientation-preserving springs.

14. The method of claim 13 wherein the one or more orientation-preserving springs'"'"' one or more rest-vectors are modified as a result of any of:

a) one or more collisions,

b) a plastic change in a material due to internal or external forces,

c) a response to user input, or a combination thereof.

15. The method of claim 8 further comprising:

defining and assigning to a selected type of spring a normalized value representing damping of the spring, such that a normalized value of zero represents an absence of damping, a normalized value of less than one represents underdamping, a normalized value of one represents critical damping, and a normalized value of greater than one represents overdamping; and

using the assigned normalized value to calculate the spring'"'"'s actual damping value, so that the spring exhibits a damping response specified by the normalized value.

16. The method of claim 1 wherein step (e) further includes:

a body for an entity being simulated with one or more components each including a defined force transmission parameter value; and

calculating;

a first portion of a body'"'"'s body mass that moves in a rigid manner, and by inference, a second portion of the mass of the body that deforms independently of the body, using defined force transmission parameters values associated with each of the one or more components of the body;

a partial acceleration of each component of the body that is independent of a motion of the body as a whole, and a partial acceleration of each component of the body that is due to an acceleration of the body as a whole;

an independent change in position and velocity of each of the body'"'"'s components, due to deformation (A);

a change in position and velocity of the body as a whole, due to a rigid motion (B);

a position and velocity of each of the body'"'"'s components relative to the body'"'"'s center-of-mass; and

an actual change in position and velocity of each of the body'"'"'s components, including both (A) and (B), and all component force transmission parameter values.

17. The method of claim 1 wherein step (f) further includes:

a body for an entity being simulated with one or more components each including a defined force transmission parameter value; and

calculating;

a total torque on the body;

an amount of force transmission of the body;

a body change in angular momentum, involving the amount of force transmission of the body;

a body angular velocity (A) and angular acceleration;

a linearized angular velocity of each of the one or more components of the body or centrifugal and coriolis accelerations of each of the one or more components of the body both collectively donated (B);

a change, due to rotation, in position and velocity of each of the one or more components of the body, including (A) or (B), and each component'"'"'s force transmission parameter value; and

a change in orientation of the body'"'"'s orthonormal basis reference frame.

18. The method of claim 1 wherein the defined force transmission parameter values of one or more individual components of an entity being simulated are changed over time.

19. The method of claim 18 wherein the change in the force transmission parameter values of one or more individual components of an entity being simulated is changed over time due to any of:

a) physical properties of a material under compression,

b) response to external forces,

c) tables of data or functions residing in a computer database or memory,

d) response to user input, or a combination thereof.

20. The method of claim 1 wherein an entity being simulated includes a component of a human body.

21. The method of claim 20 wherein the component of the human body includes any of muscle, bone, and connective tissue.

22. The method of claim 1 wherein step (d) further includes:

obtaining one or more of positions, velocities or accelerations of the one or more haptic devices on the network device that sense any of positional information, rotational information, hand motion, and other motion from a user input and return one or more resistive or push-back forces to the user on the one or more haptic devices, allowing a feel of any of resistance, collision, penetration, separation, cutting, tearing, breakage, and other motions of one or more materials of an entity being simulated.

23. The method of claim 1 further comprising:

applying with the composite simulation method on the network device a pre-determined collision detection method to detect collisions between any of one or more representations of the one or more haptic devices and the one or more individual components for each of the one or more entities being simulated to create collision-free representations of the one or more haptic devices and collision-free representations of the one or more individual components for each of the one or more entities being simulated.

24. The method of claim 1 further comprising storing physical information about a 3D model in its color data, such that each component of a four-component color maps to one of the physical quantities of mass, stiffness, damping, and force transmission.

25. A system for providing absolute positional and rotational registration of an entity being simulated on one or more graphical display devices, one or more haptic or other position sensing devices, and one or more viewpoint tracking devices, comprising in combination:

means for rigidly and physically connecting one or more display devices including one or more graphical display devices or audio devices to a mechanical linkage or harness;

means for rigidly and physically connecting one or more haptic devices to the mechanical linkage or harness; and

means for rigidly and physically connecting one or more viewpoint tracking devices to the mechanical linkage or harness; and

means for registering during the simulation, the one or more display devices, the one or more haptic or position-sensing devices, and the one or more tracking devices as hardware components to control the entity being simulated during the simulation and the aligning the hardware components for interacting with the entity being simulated during the simulation,

wherein the means for registering implements the method according to claim 1.

26. The system of claim 25, further comprising means for rigidly and physically connecting one or more devices including one or more graphical display devices or audio devices, one or more haptic devices, and one or more viewpoint tracking devices to a mechanical linkage by which the one or more devices are dynamically repositioned during a simulation, new positions being dynamically reported in real time by mechanical or other sensors.

27. The system of claim 25, further comprising:

means for registering during the simulation, the one or more graphical display devices, the one or more haptic devices and one or more tracking devices worn by one or more users to control the one or more entities being simulated and aligning hardware components for interacting with virtual objects encountered during the simulation.

28. A system for simultaneously simulating rigid, semi-rigid and flexible components of an entity, comprising in combination:

means for defining on a network device with one or more processors, one or more individual components for each of one or more entities to be simulated, wherein a three-dimensional (3D) entity includes at least four individual components combined into the 3D entity being simulated;

means for defining for each of the one or more individual components, a force transmission parameter obtained from a plurality of force transmission parameter values, such that an entity'"'"'s rigid mass is greater than zero, and less than its total mass, the plurality of force transmission parameter values including a first force transmission parameter value representing a fully flexible component, a second force transmission parameter value representing a fully rigid component and a plurality of other force transmission parameter values with values in-between the first force transmission parameter value and the second force transmission parameter value representing varying levels of semi-rigidity, wherein the selected entity'"'"'s rigid mass is calculated according to the equation;

29. The system of claim 28, further comprising:

means for rigidly and physically connecting and dynamically moving during a simulation and registering with respect to each hardware component of the simulation, with the composite simulation method on the network device one or more display devices, one or more position-sensing devices, and one or more tracking devices to control the one or more entities being simulated.

30. The system of claim 28 further comprising:

means for obtaining or calculating a plurality of positions, velocities, and accelerations for combined rigid and flexible components of an entity being simulated using a spring and dashpot model for the flexible simulation method of the composite simulation method on the network device;

means for calculating a plurality of forces and torques on an entity being simulated using any of the obtained positions, velocities and accelerations with the composite simulation method on the network device;

means for calculating one or more of any of positions, velocities or accelerations of an entity being simulated and its components using the calculated plurality of forces and torques with the composite simulation method on the network device; and

means for displaying on the graphical user interface with the plurality of graphical windows on the graphical display on the network device with the composite simulation method a two-dimensional (2D) or three-dimensional (3D) simulation view, wherein the view may contain a representation of any of the one or more entities being simulated, their components, or subportions thereof on an audio, on the one or more haptic devices, or on position-sensing devices on the network device.