VRayDistanceTex issues with mirrored CAD geometry

[Morne]

I have some CAD objects where some of these objects are mirrored in CAD

For all these mirrored objects, if they are included in the DistanceText list of objects, they do not result in correct operation
The non mirroed objects works fine as expected

VRay Next update 3.2, Max 2021

[JonasNöll]

I would assume that the normals are probably flipped on the mirrored parts. You should first make sure that all geometry has the same outward facing normals.
You can also try to export everything as OBJ again and import it back in, that also sometimes helps in those kind of scenarios.

[Morne]

Its from linked dwg file containing CAD blocks

Historically max doesnt like cad blocks much, especially if they're mirrored apparently

it was line blocks live linked and sweep modifier added. BUt because cad block......

anyway, I just redid the cad blocks by recreating the mirrored ones

[^Lele^]

Did you try resetting xForm?

[kosso_olli]

Did you try resetting xForm?

This is not a good idea on CAD objects, depending on which software they are coming from. xForm will break the surface continuity, resulting in shading artifacts for the mesh. See images for before and after. It has been like that for as long as I can remember. We avoid reset xForm at all costs, it does more harm than good.

[^Lele^]

Well, he had them mirrored already, the damage at that point was done if it had to be done, as the transform matrix (which is what xForm means) was already altered from its imported state.
Resetting negative scaling is unlikely to cause further issues, i'd wager.

Further, it's cad blocks, not converted NURBS surfaces, they are unlikely to suffer from the same set of issues.