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Creases and Mirror OP

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I ran into the following little Problem: I have one half of the low-poly cage model and feed it into the mirror OP. The mirrored closed low-polycage then goes into a subdivide OP and I get the smooth version. Everything seemed fine until I added creases to avoid having to insert extra loop on the model for harder edges.

I added those creases on the low-poly half. Unfortunally the mirrored smoothed second half seems to inverse those crease weights and those creased edges look very odd. They look fine, if I uncheck the the reverse option on the mirror node, but than I have the problem of reversed normals on the second half. I can think of few cases where this is a desirable behaviour, so I wonder if this might be a bug. Or is there a way exept adding those creases after the mirror option to avoid this problem ?!

Hope the text is somewhat clear. If not I'll post s screenshot / file.


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Hi Jens,

I wonder if that's not because of the way the reverse option works and because of the fact that the crease attributes are vertex attributes and not edge attributes (since edge attributes don't exist in Houdini). The vertex crease attribute is applied to the vertex and is intended to go to the "next" vertex. When the polygon is reversed, the "next" vertex becomes the "previous" vertex and you see what you see. Anyway, at least I think that's what's going on.

To fix it, could you keep the normals reversed until you do the subdivision? Or perhaps wrap the subdivision between two reverse SOPs that reverse and unreverse the normals? Other solutions that might work are AttribCopy, AttribTransfer, Vertex, etc...

And of course, there is always just adding the crease afterwards :)

Hope that helps.

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