bEnableProjection

[PhysX] If distance error between bodies exceeds 0.1 units, or rotation error exceeds 10 degrees, body will be projected to fix this. For example a chain spinning too fast will have its elements appear detached due to velocity, this will project all bodies so they still appear attached to each other.

[Chaos] Chaos applies a post-solve position and angular fixup where the parent body in the constraint is treated as having infinite mass and the child body is translated and rotated to resolve any remaining errors. This can be used to make constraint chains significantly stiffer at lower iteration counts. Increasing iterations would have the same effect, but be much more expensive. Projection only works well if the chain is not interacting with other objects (e.g., through collisions) because the projection of the bodies in the chain will cause other constraints to be violated. Likewise, if a body is influenced by multiple constraints, then enabling projection on more than one constraint may lead to unexpected results - the "last" constraint would win but the order in which constraints are solved cannot be directly controlled.

projection will not be applied to constraints with soft limits.