Hi! We’ve discovered that MassEntity-based Actors do not function correctly with Motion Matching.
Specifically, the UMassSteerToMoveTargetProcessor / UMassApplyForceProcessor / UMassApplyMovementProcessor / UMassCharacterMovementToActorTranslator chain of processors will directly calculate and set the final velocity on the Actor’s movement component, without setting acceleration. On the other hand, for Player Characters, player input directly sets acceleration, with velocity then “catching up” to it.
That means that if player input suddenly changes direction, e.g. from fully-left to fully-right, there is a small window during which the Player Character will have its velocity in an opposite direction from its acceleration, before gradually re-aligning. This is what allows MM’s trajectory prediction to work: it can detect near-future sharp changes in movement direction, and this info can then be fed into Chooser Tables to select a Pivoting animation.
However, since Mass Movement does not expose acceleration, trajectory prediction does not work for our Mass NPCs with out-of-the-box Mass. We have a local changelist which alters Mass to expose the cumulative steering force and use that to emulate player input for NPCs, but we’d like to check with you if Epic has any plans to address this, and if so, where would that be on the release roadmap.
Thank you