Geometry and material problem - weird atrifacts

[redtom]

Hey, I've found strange black triangles in renders. Model from ArchiCAD, in Cinema viewport everything seams OK, simple diffuse material, no bump or displacement. Any idea what could be the problem or any solution? Thanks!

[aleksandar.kasabov]

Dear redtom,

Would you mind sharing the scene in question (could be a simplified version of it where the issue is reproducible) so we can have a look? Please make sure to send the scene with all assets for it (go to File>Save Project with Assets).

Also, please specify more information about your setup. What are your V-Ray and Cinema4D versions along with your OS. Are you rendering with V-Ray or V-Ray GPU? If you are using V-Ray GPU, please specify your GPU driver and your GPU model. Thanks.

[redtom]

Dear aleksandar.kasabov,
Thanks for your quick reply. I write you an message.