Recovering sharp edges from ShrinkWrap through SubD

We are often manually redrafting complex buildings from the AEC industry for our own applications, which require very clean solid geometry and small details removed. The ShrinkWrapper can be useful in some cases, but applies more to 3D printing applications because we need to remove small details, but keep the sharpness of larger ones.

There is a simple example floating around with a shoe (or clog!) being wrapped, then converted to SubD, and manual lines being used to slice and crease back in the sharp edges.

For an application where there are hundreds or thousands of these, it isn’t feasible to do them all manually. Does anybody know of an efficient way to achieve this? Essentially, what we’d like to do is manually separate out or duplicate some original curves from the original geometry (deleting all the small features), and use these to snap the wrapped geometry back onto these with little user interaction, either through the mesh ahead of SubD and later conversion to solid, or in the SubD itself.

Any thoughts?

no way to do this automatically at the moment.

Shrinkwrap will always have a bit of a “rounded” edge that will be determined by the target edge length.

you could technically quadremesh these parts using guide curves for the stuff you wanted sharp then convert to subd and crease, but that would be a very fussy, labor intensive task.

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Hi @Christian_Rohr,

Sharpening the results of ShrinkWrap is something we plan on investigating for Rhino 9.

– Dale

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