ue5-spawn-frame-and-inheritance
Spawn Frame and Inheritance
Two actors, same code, different results — one is standing still and one is moving. That is the whole class of bug this skill covers, and it has two independent causes that produce similar symptoms:
Reference frame. A solution computed in the mover's frame, applied in world space, without the conversion. The error is a constant offset in the direction of motion, scaling linearly with speed. It has a signature that makes it easy to recognize once seen and nearly impossible to find by inspection: the bias is always in the same direction relative to travel, and it disappears when the mover stops.
Frame timing. A value read at the wrong point in the tick order, so it is one step stale or one step ahead. Error scales with speed and with step size, moves when frame rate changes, and vanishes under a debugger's slow stepping.
Both look like a bug in whatever consumes the value. Neither is.