First interior C/C + render settings

[vlado]

I don't think they ever resolved the poblem or the solution.

This is because of the red dots, I think I've explained this... they may show up as dots on the screen, but the light cache propagates them throughout the whole scene thus gradually destroying the GI solution. Before a "red dot" is encountered, all is fine, but once the light cache comes across a red dot, it quickly propagates everywhere. This explains why adding more samples makes the situation worse. Fixing the red dots problem also fixes the light cache.

The dots could be from the colorcorrect plugin.

V-Ray would typically print a warning about which object produced the invalid color. Inspect the material of that object for anything suspicious (e.g. Color Correct, bitmaps without Crop option, Falloff map etc). Note that usually, this is not the material on which the dots appear - it could be a material that is reflected in another one, for example. The warning message will give the exact location of the problem.

Best regards,
Vlado

[dlparisi]

Thanks for the info Vlado, good stuff to solve future problems.