US 11,875,094 B2Granted

Minimization function for friction solving

AssigneeMicrosoft Technology Licensing, LLC

InventorsPetar Mitrovic, Eoin Mcloughlin, Maxwell Simon Abernethy, Milan Simic, Milos Jovanovic, Nikola Nikolic, Oliver M. Strunk, Pavle Josipovic, Rory Mullane, Janos Benk

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Abstract

A physics engine executed on a processor to simulate real-time rigid body dynamics of a simulated physical system with a minimizing function between initial velocities and intermediate solver velocities is provided. The physics engine may be configured to iteratively loop through a collision detection phase, an iterative solving phase, updating phase, and display phase. The physics engine may be configured to store initial velocities for colliding pairs of bodies. The physics engine may be further configured to determine intermediate solver velocities for the colliding pairs of bodies based on accumulated results of constraint solving for each pair of bodies. The physics engine may be further configured to calculate friction velocities for that colliding pair of bodies based on the stored initial velocities and the intermediate solver velocities using a minimization function, and apply a friction force or impulse based on the calculated friction velocities.

Claims21

Dependent claims

A computing device, comprising:

a processor configured to execute a physics engine to simulate real-time rigid body dynamics of a simulated physical system including a plurality of bodies, wherein the physics engine is deterministic and does not maintain state data other than respective positions and velocities of the plurality of bodies between successive timesteps, the physics engine being configured to:
iteratively loop through a collision detection phase, an iterative solving phase, updating phase, and display phase;
in a current collision detection phase:
identify colliding pairs of bodies of the plurality of bodies;
determine collision information including a plurality of position or velocity constraints for the identified colliding pairs of bodies;
and
store initial velocities for the colliding pairs of bodies;
in a current iterative solving phase:
for each solver iteration:
for one or more colliding pairs of bodies:
for one or more position or velocity constraints between that colliding pair of bodies:
solve that position or velocity constraint;
apply a force or impulse to each of the colliding pair of bodies at a contact point of the colliding pair of bodies based on the solving of each position or velocity constraint;
and
accumulate results of constraint solving by accumulating the applied forces or impulses;
determine intermediate solver velocities at the contact point between the colliding pair of bodies based on the accumulated results of constraint solving;
calculate friction velocities for that colliding pair of bodies based on the stored initial velocities and the intermediate solver velocities at the contact point between that colliding pair of bodies using a minimization function, wherein the minimization function selects a smaller of the stored initial velocities and the intermediate solver velocities to compute the friction velocities;
and
apply a friction force or impulse based on the calculated friction velocities for that colliding pair of bodies;
in an updating phase:
update positions of the colliding pairs of bodies based on a result of the current iterative solving phase;
and
in a display phase:
output data representations of the plurality of bodies to a display associated with the computing device.

21 more elements

A method for use with a computing device, comprising:

at a physics engine executed by a processor of the computing device to simulate real-time rigid body dynamics of a simulated physical system including a plurality of bodies, wherein the physics engine is deterministic and does not maintain state data other than respective positions and velocities of the plurality of bodies between successive timesteps:
iteratively looping through a collision detection phase, an iterative solving phase, updating phase, and display phase;
in a current collision detection phase:
identifying colliding pairs of bodies of the plurality of bodies;
determining collision information including a plurality of position or velocity constraints for the identified colliding pairs of bodies;
and
storing initial velocities for the colliding pairs of bodies;
in a current iterative solving phase:
for each solver iteration:
for one or more colliding pairs of bodies:
for one or more position or velocity constraints between that colliding pair of bodies:
solving that position or velocity constraint;
applying a force or impulse to each of the colliding pair of bodies at a contact point of the colliding pair of bodies based on the solving of each position or velocity constraint;
and
accumulating results of constraint solving by accumulating the applied forces or impulses;
determining intermediate solver velocities at the contact point between the colliding pair of bodies based on the accumulated results of constraint solving;
calculating friction velocities for that colliding pair of bodies based on the stored initial velocities and the intermediate solver velocities at the contact point between that colliding pair of bodies using a minimization function, wherein the minimization function selects a smaller of the stored initial velocities and the intermediate solver velocities to compute the friction velocities;
and
applying a friction force or impulse based on the calculated friction velocities for that colliding pair of bodies;
in an updating phase:
updating positions of the colliding pairs of bodies based on a result of the current iterative solving phase;
and
in a display phase:
outputting data representations of the plurality of bodies to a display associated with the computing device.

21 more elements

A computing device, comprising:

a processor configured to execute a physics engine to simulate real-time rigid body dynamics of a simulated physical system including a plurality of bodies, wherein the physics engine is deterministic and does not maintain state data other than respective positions and velocities of the plurality of bodies between successive timesteps, the physics engine being configured to:
iteratively loop through a collision detection phase, an iterative solving phase, updating phase, and display phase;
in a current collision detection phase:
identify colliding pairs of bodies of the plurality of bodies;
determine collision information including a plurality of position or velocity constraints for the identified colliding pairs of bodies;
and
store initial state data for the colliding pairs of bodies;
in a current iterative solving phase:
for each solver iteration:
for one or more colliding pairs of bodies:
for one or more position or velocity constraints between that colliding pair of bodies:
solve that position or velocity constraint;
apply a force or impulse to each of the colliding pair of bodies at a contact point of the colliding pair of bodies based on the solving of each position or velocity constraint;
and
accumulate results of constraint solving by accumulating the applied forces or impulses;
determine intermediate state data at the contact point between the colliding pair of bodies based on the accumulated results of constraint solving;
calculate friction state data for that colliding pair of bodies based on the stored initial state data and the intermediate state data at the contact point between that colliding pair of bodies;
solve for friction at the contact point between that colliding pair of bodies based on the calculated friction state data;
in an updating phase:
update positions of the colliding pairs of bodies based on a result of the current iterative solving phase;
and
in a display phase:
output data representations of the plurality of bodies to a display associated with the computing device.

20 more elements

A computing device, comprising:

a processor configured to execute a physics engine configured to:
store initial velocities for a colliding pair of bodies;
determine one or more position or velocity constraints for the colliding pair of bodies;
solve the one or more position or velocity constraints;
apply one or more forces or impulses to each body of the colliding pair of bodies based on the solving of each position or velocity constraint;
accumulate the one or more applied forces or impulses to obtain accumulated results of constraint solving;
determine intermediate solver velocities for the colliding pair of bodies based on the accumulated results of constraint solving;
calculate friction velocities for that colliding pair of bodies based on the stored initial velocities and the intermediate solver velocities using a minimization function, wherein the minimization function selects a smaller of the stored initial velocities and the intermediate solver velocities to compute the friction velocities;
apply a friction force or impulse based on the calculated friction velocities for the colliding pair of bodies;
update positions of the colliding pairs of bodies based on the accumulated results of constraint solving and the applied friction force or impulse;
and
output data representations of the plurality of bodies to a display associated with the computing device.

9 more elements

Dependencies are inferred from the claim text.