I have been trying to figure this out, tried searching but could not find a solution.
How do I blur an object (or light) that is behind a glass?
I have attached a blend file, with a glass cube, and a cylindrical object (with emission surface) that is inserted through the glass cube. I wanted the cylindrical tube to be blurred, including the image that is transmitted through the glass.
How can that be done? Please feel free to edit the attached blend file.
What do you exactly want to do? what effect are you expecting?
For example, you can separate more passes and combine it adding some blur effect. But that’s not really good… it looks fake and it will always look more or less fake doing it that way.
I was trying to blur only the red tube’s refraction and reflection image inside the “clear” glass cube. Adding roughness to the glass cube’s material will not work.
I would say your first solution works perfectly fine! As it deals directly with the glass glossy reflections, and glass transmission (refraction) rays.