Quick answer: Unreal physics body with high rest friction stuttering when transitioning to motion? Static friction threshold abrupt - lower static or smooth via friction tween.
Pushable crate sticks then jumps; pushable barrel slides smoothly. Same friction setup, different shapes.
Lower static friction
Physical material > Static Friction < Kinetic Friction by 0.2-0.5. Threshold transition smooths.
Or tune contact damping
Higher damping smooths the stick-slip transition. Costs a touch of responsiveness.
Different materials per shape
Round vs flat surfaces interact differently. Per-shape physical materials more accurate than one global.
“Static vs kinetic friction is a physics primitive. Tune both; their gap is the stutter source.”
If pushable physics feels wrong, the static/kinetic ratio is usually the cause. Tune that first; revisit shape later.