I have a problem with the glass material. When I look at the image straight on, its fine. But when I move to an angle it turns grey. Look at the pics for what I’m talking about. What is causing that to happen?
I’m trying make the plastic inside the old Transformer toys. I’m not sure what is the best way of doing that. I’m trying glass, but it seems too reflective. What would be the best way to recreate the plastic?
using cycles.
The last pic is to show what I’m talking about.
Hard to say without seeing the file. Could be a normals issue. Or do you have multiple layers of plastic coating that might overlap each other?
Anyway, I’m not sure if I would use glass (or refractive) shaders on this:
Anything that refracts will increase the render time and might cause firefly issues. On massive glass (etc.) objects that’s a drawback you will gladly accept for the enhanced realism you will get from raytraced refraction. But the refractive effect of a thin plastic coating is negligible anyway, so why not just fake it?
Some quick and dirty tests with a rather simple glossy/transparent mix shader (could have used more samples and more careful modeling):
show nodes set up !
try to reduce the IOR glass to 1 and may try to reduce glossy to a minimum
looks like it is reflecting the sky grey may be!
happy cl
Thanks guys. Helped a lot.
Yeah it was the normals. I needed to flip that font one.
I also changed it to what you said and it looks a lot better with the mix shader.
glossy roughness 0.030 and mix shader fac 0.10
This is the node setup for the plastic material in my test render:
The Input > Layer Weight > Facing node controls the blend between transparent and glossy, with glossy getting more and more dominant at glancing angles. The Converter > Math > Add node makes sure that even when viewed straight on the material remains a tiny bit glossy. The Input > Light Path node forces Blender to use a pure transparent shader for all shadow rays, making the material effectively shadowless, which prevents objects behind the plastic cover from becoming too dark.
any doc on this light path node effect ?
I had another explanation for it more like
that the camera will see the material as glass or tranps , but indirect light will see it as transparent, this will let light through the window regardless of mesh thickness!
thanks
From my understanding this has nothing to do with “indirect” light, as it also works in a “direct light only” setup:
Left - pure diffuse
Right - diffuse/transparent mix with Light Path > Shadow Ray as controller for the mix factor.
In a pathtracer shadows are a “property” of the material casting them, not the material they are cast upon. That’s why shadow catchers are so difficult to implement. And that’s why the shaders of a material can control if the object casts a shadow or not. What the light path node does in this case, is to tell Blender:
“For every shadow ray that this material casts: use the fully transparent shader. For any other ray type (including camera rays): use the glossy/transparent mix shader.”
