@cotty said:
You can use the VCB to specify the offset (see page 13).
I know this. But this is not what I want to ask.
You can see that after push/pull a curved surface, distance between a point in new created face and its origin in old surface is not equal to offset.
I think that it may be more accurate if we could make offset 'mean' the distance between these point. I not sure and am asking for opinion.