I'm continuing on this outside shot and stumbled onto another problem.
My car-paint shader is getting transparent.
The normal shader tree is till Mix_8colors1, a component car paint shader with a texture. Everything works fine up until that point.
To make the car a bit more interesting I wanted to add some dirt and grime. I painted a simple mask for that (CarBodyDirtMap_tif) which you can see in its PPG on the left side.
The Lambert shader is the dirt, with a incidence controlled gradient to show it more at glancing angles.
Ive added this to the car paint by the Mix_2colors node, driven by the CarBodyDirtMap_tif. The mode is set to Decal (seen on the right side).
But when I render this set up, my shader gets transparent, you can see the right exhaustpipe through the car body and also the front door interiour.
I've also tried the other way around, clipping the Lambert with the map and controlling the Mix_2colors node with the gradient, but that didn't help.
I'm sure I must be missing something, I just don't know what it is. Does anybody have some idears?