Robust means the model survives edits without broken references, flipped features, or sketch instability. Proof is simple: change key parameters across the expected range and confirm rebuild success, stable mass properties, stable mating faces, and unchanged critical drawing dimensions. If it only works at nominal, it is not robust.
Decide what must stay centered, aligned, or symmetric and constrain it explicitly.
Drive sizes from a small set of master parameters, not scattered sketch dims.
