PhysxRigidBodyAPI

PhysX tuning for a dynamic rigid body. Read only when the prim also carries PhysicsRigidBodyAPI with rigidBodyEnabled true. Three columns have units-scaled parser defaults that the raw schema fallback does not reproduce.

• Applies to: Xformable

• Requires on the same prim: PhysicsRigidBodyAPI

• Read only when listed in usd-schemas.

• Uses blocks: stage_units

What USD population writes

Every declared attribute is published at its resolved value. Five columns are rewritten when unauthored, and CREATED on any prim with PhysicsRigidBodyAPI even when this API is not applied: sleepThreshold, stabilizationThreshold, maxDepenetrationVelocity (units-scaled), maxLinearVelocity (1e16) and maxContactImpulse (FLT_MAX). The producer’s values equal the consumer’s absent-column defaults, so on a producer-populated stage the raw schema fallbacks never reach the consumer.

Columns

Raw fallback is the USD schema value. Producer writes is what ovstage population puts in the column for a USD stage. Parser default applies on the consumer when the column is absent, in stage units. diverges means writing the raw fallback literally parses differently from omitting the column (the parser default): USD population may well publish that very value for an unauthored attribute, so the marker is about the column being present, not about its value.

Column	Type	Units	Raw fallback	Producer writes	Parser default	If absent
physxRigidBody:linearDamping	float32	1/s	0.0	resolved USD value (authored, else raw fallback)	0.0	0.
physxRigidBody:angularDamping	float32	1/s	0.05	resolved USD value (authored, else raw fallback)	0.05	0.05.
physxRigidBody:maxLinearVelocity	float32	length/s	inf	when unauthored: 1e+16 (column created even without the API)	1e+16	1e16, effectively unlimited. inf is clamped to the same value.
physxRigidBody:maxAngularVelocity	float32	deg/s (deg_to_rad)	5729.58	resolved USD value (authored, else raw fallback)	5729.58	100 rad/s (5729.58 deg/s). Authored values are clamped to 1e16 deg/s and converted; negative values are ignored.
physxRigidBody:sleepThreshold	float32	length^2/s^2	5e-05	when unauthored: 5e-5 * (10 / metersPerUnit) ** 2 (column created even without the API)	5e-5 * (10 / metersPerUnit) ** 2 diverges	Units-scaled default: 5e-3 on a meter stage, 50 on a centimeter stage. Writing the raw schema fallback 5e-5 on a centimeter stage makes the body sleep 10^6 times too eagerly.
physxRigidBody:stabilizationThreshold	float32	length^2/s^2	1e-05	when unauthored: 1e-5 * (10 / metersPerUnit) ** 2 (column created even without the API)	1e-5 * (10 / metersPerUnit) ** 2 diverges	Units-scaled default: 1e-3 on a meter stage, 10 on a centimeter stage.
physxRigidBody:maxDepenetrationVelocity	float32	length/s	3.0	when unauthored: 3 / metersPerUnit (column created even without the API)	3 / metersPerUnit diverges	Units-scaled default: 3 on a meter stage, 300 on a centimeter stage.
physxRigidBody:contactSlopCoefficient	float32	none	0.0	resolved USD value (authored, else raw fallback)	0.0	0.
physxRigidBody:maxContactImpulse	float32	mass*length/s	inf	when unauthored: FLT_MAX (column created even without the API)	FLT_MAX	Unlimited.
physxRigidBody:cfmScale	float32	none	0.025	resolved USD value (authored, else raw fallback)	0.025	0.025.
physxRigidBody:solverPositionIterationCount	int32	none	16	resolved USD value (authored, else raw fallback)	16	16.
physxRigidBody:solverVelocityIterationCount	int32	none	1	resolved USD value (authored, else raw fallback)	1	1.
physxRigidBody:enableCCD	bool8	none	false	resolved USD value (authored, else raw fallback)	false	Off.
physxRigidBody:enableSpeculativeCCD	bool8	none	false	resolved USD value (authored, else raw fallback)	false	Off.
physxRigidBody:disableGravity	bool8	none	false	resolved USD value (authored, else raw fallback)	false	Gravity applies.
physxRigidBody:retainAccelerations	bool8	none	false	resolved USD value (authored, else raw fallback)	false	Off.
physxRigidBody:enableGyroscopicForces	bool8	none	true	resolved USD value (authored, else raw fallback)	true	On.
physxRigidBody:solveContact	bool8	none	true	resolved USD value (authored, else raw fallback)	true	On.
physxRigidBody:lockedPosAxis	int32	none	0	resolved USD value (authored, else raw fallback)	0	No locked translation axes. Bitmask x=1, y=2, z=4.
physxRigidBody:lockedRotAxis	int32	none	0	resolved USD value (authored, else raw fallback)	0	No locked rotation axes. Bitmask x=1, y=2, z=4.

Known divergences

• fragile physxRigidBody:sleepThreshold: The authored-bit gate that protects units-scaled defaults is a no-op on ovstage (hasAuthoredAttribute is always true), so the default is passed through the clamp. Every current default lies inside its clamp range; a future default outside it would be clipped on ovstage only. Same for stabilizationThreshold and maxDepenetrationVelocity.