Sections in Vray

I’m experimenting with rendering a model in Vray at includes a section cut. I’m getting some artifact where an uncut component passes through one that is cut. Note the surface of the screw where it passes through the wing nut and the O-ring around the piston.

I could, of course, cut them in half for real but I’d like to t be able to make this work without resorting to that. Any ideas?

I was getting a sort of footprint on the ground at the bottom of the cup but I moved the background down a tiny bit and that went away.

I’d also like to get more light inside the cup but so far I’m not having a lot of success there. @mihai.s gave me some suggestions like using a Rectangle light pointed into the cup as well as a dome light. I’ve done that and I’ve got a spotlight aimed in their, too.

FWIW the faces on the section cut are actual faces generated by TIG’s Section Cut Face plugin. For the time being I’m using the sketchy diagonal line materials from the native Patterns collection. I plan to replace it with something else more suitable if I can work out the section artifacts.

Can you share your model? I’d be curious to see the setup. DM if you don’t want to share it with the world :wink:

Thanks Eric. File sent.

FWIW I did go ahead and make a copy of the file and used Zorro 2 to split the wing nut, cap, and cup in half but it’s not my ideal solution.

I would try to use the native section slices in vRay to render it but I haven’t done anything like this where one part is grouped and sliced and the other is whole.

I could give a look on Thursday (already past my bed time here, but I’m helping the young one with math homework).

See my reply via email. But for the community, no need to split it in half unless you want to. The issue is that the screw and wing nut share the same inside faces…hence z-fighting carries over into V-Ray render.

Scaling the screw down by .999 fixes it:

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That’s weird but thanks Mike. I was going to scale the threads in the cap up by half a percent so they would make workable threads if I 3D print the thing. I don’t really understand why that happens, though.

And @bmike thanks. Looks like it’s sorted.

It looks like the same kind of rendering artifacts you get from ghost faces.