Glass Reflections - it's all about the bump

Today I'm discussing using bump maps for reflections in glass. I usually see glass reflections in 3D having perfect reflections. You never really see this in reality though. There is always some bend and distortion in the glass. There are others that do use a bump map to have the reflection act more realistic. Often though, a noise map is used in the bump slot, and I haven't seen this done properly.

In reality each pane of glass has air pressure on it, forcing it to bow in or out. The frames or mullions keep the edges in place though. There is nothing wrong with using a noise map for the bump, it's how it's distributed throughout the glass between the glass frames. Often I see the same noise map passing from one pane of glass to another. That is incorrect.

The trick to getting the same map on every face is using the UVW modifier on your glass and selecting Face for the Mapping type.


  1. can you be more explicit ?

    what kind of map do you apply as a bump map ? a noise map or a white rectangle with a black line contour ?

    best regards

  2. The map I used for the bump was created in photoshop. In the image above, when it says Controlled Image Map, and on the right it has a square image with a black border that fades to a white center; that's the map that I created in photoshop.

  3. I thought believability is the most important in art, at least that was what I was thought in art college.

  4. personally I would combine the 2, have a mix of the edge bitmap and a very subtle, slight noise map.

  5. I'm struggelig, im only getting a wavey glas like thick water and not the straight and flat surfaces with different angels. You got any how-to with values to share? :)

  6. how to create a transparent glass being reflected at the same time? I mean glass can be seen through and being slightly reflected. Thanks for the help