PxJointLinearLimitPair

Defined in include/extensions/PxJointLimit.h

Inheritance Relationships

Base Type

public PxJointLimitParameters (PxJointLimitParameters)

class PxJointLinearLimitPair : public PxJointLimitParameters 

Describes a two-sided limit.

Public Functions

inline PxJointLinearLimitPair(const PxTolerancesScale &scale, PxReal lowerLimit = -PX_MAX_F32 / 3.0f, PxReal upperLimit = PX_MAX_F32 / 3.0f, PxReal contactDist_deprecated = -1.0f)

Construct a linear hard limit pair.

The lower distance value must be less than the upper distance value.

Parameters

lowerLimit – [in] The lower distance of the limit
upperLimit – [in] The upper distance of the limit
spring – [in] The stiffness and damping parameters of the limit spring

inline bool isValid() const

Returns true if the limit is valid.

Returns: true if the current settings are valid

inline bool isSoft() const

Public Members

PxReal upper

the range of the limit.

The upper limit must be no lower than the lower limit, and if they are equal the limited degree of freedom will be treated as locked.

Range: See the joint on which the limit is used for detailsDefault: lower = -PX_MAX_F32/3, upper = PX_MAX_F32/3

PxReal lower

PxReal restitution

Controls the amount of bounce when the joint hits a limit.

A restitution value of 1.0 causes the joint to bounce back with the velocity which it hit the limit. A value of zero causes the joint to stop dead.

In situations where the joint has many locked DOFs (e.g. 5) the restitution may not be applied correctly. This is due to a limitation in the solver which causes the restitution velocity to become zero as the solver enforces constraints on the other DOFs.

This limitation applies to both angular and linear limits, however it is generally most apparent with limited angular DOFs. Disabling joint projection and increasing the solver iteration count may improve this behavior to some extent.

Also, combining soft joint limits with joint drives driving against those limits may affect stability.

Range: [0,1]Default: 0.0

PxReal bounceThreshold: determines the minimum impact velocity which will cause the joint to bounce

PxReal stiffness

if greater than zero, the limit is soft, i.e.

a spring pulls the joint back to the limit

Range: [0, PX_MAX_F32)Default: 0.0

PxReal damping

if spring is greater than zero, this is the damping of the limit spring

Range: [0, PX_MAX_F32)Default: 0.0

PxReal contactDistance_deprecated

The distance inside the limit value at which the limit will be considered to be active by the solver.

As this value is made larger, the limit becomes active more quickly. It thus becomes less likely to violate the extents of the limit, but more expensive.

The contact distance should be less than the limit angle or distance, and in the case of a pair limit, less than half the distance between the upper and lower bounds. Exceeding this value will result in the limit being active all the time.

Making this value too small can result in jitter around the limit.

Default: depends on the joint