I am still trying to finish the house project I have been fiddling with the last few weeks. I was about to wrap it up when I remembered I had planned to make a better map for the reflection in the windows. I have a cylinder mapped with sky and trees, and it had to be different from the image I use for the background. Ultimately I hope to find a way to solve both background and reflections in one shot but for now this is how I pulled it off.

The map on the cylinder was something I made in a hurry, rather badly, counting on the fact it won’t show much as a mirrored image. Well it does, looks unnaturally blurry and has a wrong scale. This kind of sloppy work has a tendency to haunt me, I later have to use something in a hurry for a different project and I end up using the same terrible map forever. Older maps I used seemed great to me some time ago and now I look at them and they look terrible, seems like my standards have evolved.

So today I am using Gimp, a nice background texture from CGtextures.com and some cut trees to make a panoramic strip of scenery, dark trees on the bottom half and blue sky with some clouds on top, and it has to be tileable so it can wrap well around my cylinder. After I make a nice map I will think some more about the distortions that should appear in the reflection. Blender renders a test and I’m going to the window to study the buildings across the way.

Here is a question for you: when in need to observe, say, how a real tree looks, do you 1.look out a window or 2.google “tree” ? 🙂 I’m not testing geekiness, just climate 😛 I’m lucky to have trees around our place and it’s spring.

So, I looked and there is of course distortion caused by the panes not being perfectly flat, so I should apply some clouds-type noise on the normals of the windows. There is also blurriness, more exact the image is slightly offset by the second layer of glass. Of course the window also is a bit dirty.
Blending time over for today! I’ll try to get it finished tomorrow…

edited next day:

This was the first, ugly map:

Actually the mirroring and copy-paste trees didn’t show in my render, as the windows are small. This would show in larger glass areas.

This is the new map, hopefully closer to what I need:

I think the double-image blur effect can be experimented directly in Blender, by putting the texture on two slightly offset channels. I will try this another time.

I also tried to distort a bit the reflection using a map on the normal channel but I don’t think it really shows with this type of windows.

My glass settings might have gone a bit off as I kept trying this and that and being late in the night, so I’m not sure it’s a really good glass. I’ll have to look up some glass tutorials, the difficulty is I keep finding tutorials for rendering a glass of wine using caustics.

On to the finished render.