Why does physics behave wrong after SetActorScale?

Physics body geometry caches at simulation start. Toggle Simulate Physics off then on after scale change; engine rebuilds body.

Better: use SetWorldScale3D before play?

In editor or BeginPlay, scale is applied before physics activates. Runtime scale changes need explicit refresh.

PrimitiveComponent::SetWorldScale3D respects physics body. RecreatePhysicsState() forces rebuild without toggling Simulate.

Quick answer: After scale, call RecreatePhysicsState() on the component. Or toggle Simulate Physics off then on.

Scale up an enemy at runtime. Collision still uses old size. Physics body geometry cached.

actor->SetActorScale3D(FVector(2.0f));
auto* prim = actor->FindComponentByClass<UPrimitiveComponent>();
if (prim) prim->RecreatePhysicsState();

RecreatePhysicsState rebuilds the body to match new bounds. No more scale/collision mismatch.

Scaled enemy collides at new bounds. Without recreate: collision matches original.

“Scale. Recreate. Match.”

For SetActorRotation snap, see rotation. For mass spawn collision, see mass spawn.

Recreate physics. Scale fits.