glass material - strange refraction [with IMG]

[mesutcapkin]

Hi Mattia.
My guess is: it's a matter of refraction.
I'd say, have a look at e.g. some amber-pictures. The ones in which flies or such were cought up in thousands of years ago. You'll see that those tiny flies will appear giant.
I guess, it' similiar in your case.
Your first render shows a massive glass block, the 2nd one shows a sphere that has two thin glass walls, that surround a space of (almost) NOT refracting air.

Have a look at reference photos, that show such situations and you'll see similar results.
Well, at least, I guess so.

Mesut.

[mattjakob]

mh. sorry I dont get you explanation...
the object inside the inner sphere should have a refraction (projected on the inner surface) because it's made of the same glass of the first sphere. So what I'd expect to have is a deformed cube projected on the second sphere and another deformation of this image made by the outer sphere and projected on its surface. In practice I should see a sort of doubled distortion!

What I think is more likely is that there's some setting saying the renderer how deep to go in the refraction.... In such way in order to avoid having the cube distorted I could set that parameter to 0. It would be very useful (at least for me) to have a material looking like glass (trasparent, reflecting the environment and so on) but which doesnt deform the objects put in it (I know is not a real-life thing)........

[mattjakob]

Ok. I'm getting pedant...
but looking at the rendering process... I noticed this other thing:

http://img406.imageshack.us/img406/8778/sp3dg1.jpg

you clearly see that the rendered sphere is a little smaller than the one drawn in the viewport while modeling... someone does know why?
(maybe is due some setting on the film/aspect ration....)

[DarkFlite]

The rendered sphere is slightly off size because of the "Render Perfect" option used on a Primitive. (At least thats my best guess - that setting rounds out the sphere at the render stage with less polys in the editor.)


The reason you see less distortion when you have a sphere inside a sphere is because when the rays travel thru two surfaces the angle at which they bend is adjusted twice, and it cancels out. Effectivly you have a a hollow ball. Raypaths are calculated whenever they hit a surface - the interior of a model doesn't hae any properties, only the polys making up the skin.

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