SubD/mesh extrude difference

Hi McNeelies or anyone else with a better understanding of SubD and mesh than me
Why is it that the selection in the upper screen grab results in two different extrude results? On the SubD the extrude “pulls” the whole surface - on the mesh only the selected faces are extruded (and that’s what I would expect). Is there a reason for the SubD behaviour, can it be changed or is it a bug?

TIA, Jakob

That looks wrong. Such an enclosed region extrusion behaviour would badly limit design options. This is how things work in likely all typical mesh based SubD apps:

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@hifred Exactly! That is - in my eyes - the expected behaviour. Especially because this is what you get, if you extrude the faces one at a time (see top screen grab). Same thing if you leave more than 2 SubD patches in between the selected faces (only select every 3 face instead of every 2). I don’t get why the extracted control polygon behaves differently than an actual mesh? I know SubD are not meshes, but I thought that what we manipulate on screen is basically the control polygon.


Hi Jakob - that’s a bug and reported as item RH-52351.

Thanks @wim :slight_smile: