Thick Glass

[glorybound]

I am working on a scene with glass walls. I would like the edges to have a green tint. What's the best way to accomplish this? I tried a bunch of things, but nothing is working for me.

[Macker]

The dark edges of glass are caused by total internal reflection/refraction, and what you are seeing is all the way through the long part of the glass with light being absorbed as it travels through it (Hence it being so dark). The often green hue/tint to this is caused by small amounts of iron impurities within the glass.

If you are after realism I wouldn't add a colour to the reflection or refraction - as this isn't what happens in real life.

The way to approach this realistically is to use the fog colour, as it is "thickness dependant" i.e. it will let light through the thin part of the glass but not as much through thicker parts of the glass.

I would start with the settings for a standard/photoreal glass such as this;

Pure black diffuse
Pure white reflection
Pure white refraction
Fresnel reflections with an IOR between 1.5 and 1.6

This should give you a pretty solid glass base from which to work from. Now would be the time to start playing around with the fog colour to introduce the dark green tint at the edges. It might be worth taking the fog multiplier down to a tenth, or even hundredth otherwise it will be very sensitive to any adjustments you make to the colour.

The bias controls the "falloff" point between the thick & thin parts of the glass, for lack of better words. Generally speaking though I never really need to adjust this.

Once you've done this you should have some pretty nice looking, physically based glass.

[glorybound]

but, it's adding it to all the glass. I just want it along the edge, to make the glass look thick.

The fog colour will add the green tint.

[Macker]

See edited post

[glorybound]

I'll give it a go, thanks.

[voltron7]

+1 for the fog method...

[mario74]

+1 for Vray Dirt

[Macker]

+1 for Vray Dirt

VRay Dirt to add a green tint/edge to glass?

[mario74]

VRay Dirt to add a green tint/edge to glass?

to darken the edges!

[Macker]

to darken the edges!

Seems like a convoluted way to do it, and will result in something not physically based? In which slot would you put the VRay Dirt?

[mario74]

hmm, i misunderstood...

i thought, glorybound is searching for a dark area IN the glass AT the edges.

well, than fog is your choice and exit color in reflection.

[Macker]

Ahhh fair enough, I was hoping you'd reveal a new technique I hadn't considered!

[Morne]

the quick cheating way is to just subobject select the edges and apply greenish dark to the edges

[voltron7]

Hi Bobby,

Another nice thing about the fog is that once you get it how you like, you can easily control the effect.
I just finished a job with lots of glass walls and if you think it would help I can upload a mat file for you to test out.
Here is a small example of how it came out...
(This phase was solely for picking Sherwin Williams paint colors, so it is totally empty and stark, but exactly what they wanted.
I ended up De-saturating the green a bit just for these, so it would not draw attention from the colors they were trying to choose.)

Please don't slam this too much guys, I know it is not a real "Hero" shot or even special, just what I thought was decent glass effect...

mat filevoltron7 glass int2.zip

[glorybound]

yes, please. I would love ti check out the material, because mine is not working.