
This might sound weird but for example when I make a cross with two rectangles when I then render the image the place where the two objects cross over it creates black dots. Is there any render option to remove that?
Ok like that. 
Does anyone know what’s causing it?
@itzCatz: Your problem is “z-fighting”.
I have read that LuxRender handles z-fighting in a less ugly way, so you could try that.
Really, though, I think you could find a way to model the shape so that it works. How about applying a “Union” Boolean Modifier?
-rking
rking is right, it’s called z-fighting and you can read about it here:
For the object you are showing in the first post, just make sure you have no faces overlapping where the 2 rectangles meet. See attached file.
Randy
Attachments
example.blend (400 KB)
