SubD Vertex Nudge/Move

I have searched but couldn’t find any report of it: Using nudge on SubD vertex sometimes results in moving in different directions. I nudge the vertex on X+, but it moves in X-,Y-,Z- at the same time. Even nudging in different directions after this continues movement locked in the same direction.

“Use CPlane axes” is selected in my nudge direction options.

In this video I nudge the vertex first in Y+ direction, then in X+ direction, and lastly in Z+ direction but it always go down backwards diagonally.

@ufubo Can you share a file showing that behavior? I don’t see it here.

Is your gumball world-aligned or cplane-aligned? Could you also check how much the control polygon vertex has moved (so in flat SubD display mode), in the CPlane coordinates, before and after the nudge?

It behaves normal in flat display mode. Let’s try to reproduce:

I have added a box with two points on two corners, just under the selected vertex.

Select the same vertex in smooth mode, shift to flat display mode, and nudge it down/up 1mm using PgDwn/Up in flat mode: It will behave normal.
Then do it in smooth mode: Nudge down 1mm and check the real position by shifting to flat mode. It will be on the lower point. Then switch back to smooth mode again and nudge “up”, it will move even lower to the point at the bottom. Try using nudge in different directions and it will keep moving down diagonally.

Nudge.3dm (3.0 MB)