NVIDIA(R) PhysX(R) SDK 3.4 API Reference: Px1DConstraint Struct Reference

NVIDIA PhysX SDK 3.4 API

Px1DConstraint Struct Reference
[Physics]

A constraint. More...

#include <PxConstraintDesc.h>

Collaboration diagram for Px1DConstraint:

List of all members.


Public Attributes

PxVec3 linear0
 linear component of velocity jacobian in world space
PxReal geometricError
 geometric error of the constraint along this axis
PxVec3 angular0
 angular component of velocity jacobian in world space
PxReal velocityTarget
 velocity target for the constraint along this axis
PxVec3 linear1
 linear component of velocity jacobian in world space
PxReal minImpulse
 minimum impulse the solver may apply to enforce this constraint
PxVec3 angular1
 angular component of velocity jacobian in world space
PxReal maxImpulse
 maximum impulse the solver may apply to enforce this constraint
union {
   struct SpringModifiers {
      PxReal   stiffness
 spring parameter, for spring constraints
      PxReal   damping
 damping parameter, for spring constraints
   }   spring
   struct RestitutionModifiers {
      PxReal   restitution
 restitution parameter for determining additional "bounce"
      PxReal   velocityThreshold
 minimum impact velocity for bounce
   }   bounce
mods
PxReal forInternalUse
 for internal use only
PxU16 flags
 a set of Px1DConstraintFlags
PxU16 solveHint
 constraint optimization hint, should be an element of PxConstraintSolveHint

Detailed Description

A constraint.

A constraint is expressed as a set of 1-dimensional constraint rows which define the required constraint on the objects' velocities.

Each constraint is either a hard constraint or a spring. We define the velocity at the constraint to be the quantity

v = body0vel.dot(lin0,ang0) - body1vel.dot(lin1, ang1)

For a hard constraint, the solver attempts to generate

1. a set of velocities for the objects which, when integrated, respect the constraint errors:

v + (geometricError / timestep) = velocityTarget

2. a set of velocities for the objects which respect the constraints:

v = velocityTarget

Hard constraints support restitution: if the impact velocity exceeds the bounce threshold, then the target velocity of the constraint will be set to restitution * -v

Alternatively, the solver can attempt to resolve the velocity constraint as an implicit spring:

F = stiffness * -geometricError + damping * (velocityTarget - v)

where F is the constraint force or acceleration. Springs are fully implicit: that is, the force or acceleration is a function of the position and velocity after the solve.

All constraints support limits on the minimum or maximum impulse applied.


Member Data Documentation

angular component of velocity jacobian in world space

angular component of velocity jacobian in world space

struct { ... } ::RestitutionModifiers Px1DConstraint::bounce

damping parameter, for spring constraints

a set of Px1DConstraintFlags

for internal use only

geometric error of the constraint along this axis

linear component of velocity jacobian in world space

linear component of velocity jacobian in world space

maximum impulse the solver may apply to enforce this constraint

minimum impulse the solver may apply to enforce this constraint

union { ... } Px1DConstraint::mods

restitution parameter for determining additional "bounce"

constraint optimization hint, should be an element of PxConstraintSolveHint

struct { ... } ::SpringModifiers Px1DConstraint::spring

spring parameter, for spring constraints

velocity target for the constraint along this axis

minimum impact velocity for bounce


The documentation for this struct was generated from the following file:



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