lighting through glass, edge lighting

[edarockt]

hello everybody,

i have a strange problem when I am rendering a lamp.
what I want to get, is attached as a picture.



When clear glass with polished edges is illuminated just from one side, than the lighting is going trough the body and is shining at the edge.
it doesn´t matter what I am trying, I am not getting this effect.
attached another picture of how a prerendering looks like.


So my question are. What kind of glass material should I use (properties) and where must the light be positioned.

thank you very much.
Aram

[fooprobe]

That's a tough one. If you get the angle right, you can place a skinny rectangular light on the back edge and it will refract, but at many angles you'll see nothing. I'd recommend using thin emissive rectangles just inside the edges you want to glow, rather than trying to mimic a "real" light.

[mcvltd]

I would explode the glass objects, keep the large flat sides as glass but give the edges a completely different material with an emissive layer. It's a big cheat but hey ho!

[fooprobe]

Yep that's a good solution too. Just watch the refraction IOR, it usually needs to be turned way down (close to 1.0) on single surfaces, otherwise it's very exaggerated. And fog color too.

[Micha]

I found a very interesting option I never used before - the emission color of the refraction fog. Looks like it's added for this kind of look. It works for "complex" edges too - see quick example.

[fooprobe]

That's neat... I'm away from vray or I'd try it now - so there's a multiplier for intensity? I wonder how it knows to make the narrow edges glow but not the wide face. Wonder what happens with a more complex object.

Too bad there's no manual for this.

[Micha]

I played with it a little bit - the intensity is quite limited. The fog density controls the constant color. I'm not sure it's possible to get a bright glow at the edges without a light glow on the wide face.

[fooprobe]

Too bad. Thanks for checking it out.