strange sadows

Hello, I’m rendering a building that uses a material in cycles.

The material itself is quite simple.

My problem is, some parts of the building receive a strange shadow

it seems there is no object projecting its shadow on this walls, but the renders shows otherwise.

I’ve tried to apply no shadow to that faces, but with the same result.
I’ve also tried to invert the normals, but that doesn’t work either.


what can I try to fix this issue?

TIA.

This looks more like a normals’ issue. Has this mesh been imported into Blender?
Please provide a simplified version of the file for us to have a closer look.

I agree with Ikari. It seems to be a Normal issue. Select the object and access the Data (the icon is a triangle) tab in Properties Editor. Check “Smooth” and enter a valor of 30º.

Hello
This data was imported into blender from a 3ds file, and the 3ds file was imported itself from a rvt (revit) file.

I made the import process again, from revit to 3dmax and to blender and the issue is gone now.

will have your suggestions in mind in case i run into this again (which is very possible), but for now i will close the thread as solved.

thanks for trying.