ReadonlyjointWhether a §28 joint motor's maxTorque / maxForce is a hard ceiling
on the effort the motor may apply (PH-22e, 2026-08-08).
The odd one out of this record, and deliberately so: the other three
answer "does this value reach the solver at all", and this one answers
"does it mean what §28 says it means". Both Rapier adapters take the value
— it is not dropped — and hand it to configureMotorVelocity as a
ForceBased strength gain, so a motor authored with maxTorque: 50
is stronger than one authored with maxTorque: 5 but does not stall at
50 N·m. Rapier 0.19.3 exposes no motor-force ceiling in JS, so no
declaration of true is available there.
A solver whose motor limit is a genuine cap — Box2D's maxMotorTorque is
the canonical one — declares true, and §90's compatibility tables then
show the difference instead of burying it in an adapter's prose. This is
the only member of PhysicsTuningCapabilities whose false means
"applied, differently" rather than "not applied", which is why it carries
its own paragraph rather than a one-line entry.
ReadonlyrollingWhether PhysicsMaterial.rollingFriction reaches the solver (§25).
ReadonlysleepWhether PhysicsWorldOptions.sleeping's three thresholds
(linearThreshold, angularThreshold, timeThreshold) reach the solver
(§32).
SleepingConfig.enabled is deliberately not part of this: an adapter that
cannot turn sleeping off can always refuse it outright, and both Rapier
adapters do honour enabled (RigidBodyDesc.setCanSleep).
ReadonlyspinningWhether PhysicsMaterial.spinningFriction reaches the solver (§25).
Which accepted tunables an adapter actually applies (§25, §32, §37).
§37 fixes PhysicsCapabilities's six fields, so this is an additive seventh rather than a re-shaping of them: every field here answers for a value the stable API already accepts and validates, and whose only other possible fate is to be taken and dropped. Silent accept-and-ignore is the one outcome this repository does not allow — a coefficient a solver never reads is a simulation that differs from the one that was authored, with nothing on screen or in the log to say so — so an adapter answers here and
PhysicsWorldwarns once when an authored value meets an adapter that cannot honour it.falseis not a defect: no Rapier 0.19.3 build exposes rolling or spinning friction, or any sleeping threshold (both verified against the typings and the wasm — seephysics-rapier's adapter headers). It is a statement of where the value stops.