Round Edge Shading on CAD models doesn't respect double sided material for flipped polys

[YabbieSandwich]

I have a mesh that has been converted from CAD. It is a complex surface and the some of the polygons are flipped. This is easily resolved by using the double sided material option, but the Rounded Edge Shading doesn't seem to recognise that, so that any edge that shares flipped polygons will not have the rounded edge effect.

I've attached two images of a small section of the mesh, the first is the discontinuous rounded edge shading effect when rendered in the V-Ray RT window, the second is a shaded mesh view with double-sided material disabled to show the flipped polys causing the problem.

Obviously, it would be ideal to fix the mesh and make all the polys face the correct way, but this can be impractical & time consuming with a complex CAD mesh, and automated tools do not always work with crazy CAD meshes. So, would it be possible to allow the V-Ray Rounded Edge Shading to respect the double sided material setting?

Interestingly, the Modo material rounded edge shading does respect double sided materials, but breaks in other areas.

Thanks,
Will

[boyan]

Hey,

Thank you for the post. There is a nice command in Modo called "poly.align" drag and drop it to Command tab and you can assign a key to it.

Cheers,

[YabbieSandwich]

Thanks Boyan, yes I know the Align command and it works on simple examples like above, but it does not work well on complex CAD meshes, as the polygon flow is inconsistent and it can't work out what needs flipping and what doesn't. And to go in and flip the polygons by hand or retopologize the mesh would take forever.

[YabbieSandwich]

I've continued to investigate workarounds for this problem - the Align command in Modo seems to be quite reliable now which is good, but it doesn't flip the Vertex Normals, so you still end up with shading problems if you want to use the Vertex Normal map for shading. You can flip polygons by hand, which does seem to flip the Vertex Normals, but on a complex mesh this can take many hours to do.

I have asked on the Modo slack/forums if it might be possible to have the Align command also update the Vertex Normal map, or at least keep any flipped polygons selected so that the Vertex Normals can be easily manually inverted.