@thomthom said:
You apply crease to the corner vertices - that avoids the rounding.
In SUbD v2 there is a new default subdivision mode that will keep corners sharp. (Can be change off course.)
I've been modelling this car with using mirrored components to create symmetry:
[attachment=3:3jayf6gc]<!-- ia3 -->2016-04-16_13h52_32.png<!-- ia3 -->[/attachment:3jayf6gc]
Corners - ok. But the whole edge between the two components appears as creased and you can't un-crease it because it's a contour
[attachment=2:3jayf6gc]<!-- ia2 -->ControlMesh.png<!-- ia2 -->[/attachment:3jayf6gc]
[attachment=1:3jayf6gc]<!-- ia1 -->SubDividedInHalves.png<!-- ia1 -->[/attachment:3jayf6gc]
[attachment=0:3jayf6gc]<!-- ia0 -->SubDividedAsOne.png<!-- ia0 -->[/attachment:3jayf6gc]
So one approach could be to treat everything inside a group/component as one solid just for the sake of a smooth transition. In the given case - group the two halves(without having them exploded) and then apply SubD. Instead of giving the "nested group" error, this could be used to treat the two pieces as one and get the edge between them flowing like the other loops