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Topic: How to repair damaged normal patterns in a trimesh.

I have been bothered lately by how to fix patterns in trimesh smoothing where many normals can wind up having the right inversion, but some might be inverted in the wrong place, leading to damaged/undesired normal patterns.  So my idea at first to fix this was to have a piece of code in AoI be updated so that individual faces could be selected to use with the "invert surface normals" tool in trimesh editor, which would be very handy, but for now I have come up with a sort of work around for this problem I have run into many times.

The solution is to select the negative part of the mesh, extract the faces to another mesh, invert the normals of that mesh, then rejoin it to the extracted positive faces of the original, or the negative cleared part of the original.

Last edited by doomseer (April 3, 2017, 11:25 pm)

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Re: How to repair damaged normal patterns in a trimesh.

So my idea at first to fix this was to have a piece of code in AoI be updated so that individual faces could be selected to use with the "invert surface normals" tool in trimesh editor, which would be very handy

That's a reasonable request.

Where did the inside-out surfaces come from? Result of some kind of a mirroring procedure, I presume? I have also sometimes seen imported models to appear "inside out".

Last edited by peteihis (April 4, 2017, 1:21 am)

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Re: How to repair damaged normal patterns in a trimesh.

it can come from either a mirroring scale like scaling (x,y,z) for (-1,1,1) or from joining converted to trimesh objects the wrong way, like for example spline meshes where one is turned 180 degrees to the other, and sometimes from weird boolean or other things like extruding in a negative space way with extrude object script.

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May it be when darkness falls
Your heart will be true

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