How do I make blurry/dirty glass?

Hi guys,

Is there any way to blur the refraction on the glass material? Or some other way to fake it, so when one is looking through the glass, the image is blurred?


Glass Seems to be A Tricky Bit of Business right now. Reflections, Blurriness all have issues, my immediate suggestion is add a reflection Cube to the material, and blur it in Photoshop…

Maybe have some kind of vertex based distortion/scattering in the shader?

Although, that might require you to increase complexity of your mesh at the point where it’s supposed to be refracting/blurring. And if this area is not static but changes/moves, well that makes it even more interesting to accomplish. :slight_smile:

I had a similar effect I was trying to achieve recently (etched glass and glossy refractions).

The closest I managed to get it to work was to pipe in a high frequency noise into the refractive index, clamped between 10% -+ of my target IOR.

The problem is, the engine takes a couple of seconds to update the refraction, so your fuzzy glass has a weird swimming effect. Not ideal.

Thanks for answer, Crow87. It’s a nice idea, gonna give it a shot. Have you ever tried the same high frequency noise piped into the normal? May give it sort of a roughness effect. I think, in some cases, sticking a fog volume behind the glass may simulate similar effect, but of course it’s still not ideal.

Ideally I’d like to figure out a way to blur the overall image based on a mask from the glass as a post process, but I’m still working that out. I’ll post back if I find anything.

I remember in UDK, I managed to use blur post process node to blur the cubemap capture actor output texture. Maybe something like that can work, it it is used with refraction input?