Am 08.01.2012 17:41, schrieb crowbait:

> I made a bump_map bitmap.
> I expected it works like a convex lens.

...

> But why the normal effects different for X and Y axes?

Even though bump_map bitmaps have been around in POV-Ray for quite some 
time, they've always been flawed (unfortunately they're not trivial to 
fix); consequently, bump maps are good for some more or less random 
distortion, but that's about it. I've never examined how the issue 
affects transmitted light, but I guess what you see is the result of it.

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