Indigo Renderer Forum

probably the fresnel effect...

That is quite odd... perhaps a normal smoothing, or normal reversal issue?

ok i'll check it out

radiance wrote:i forgot to mention that when setting the IOR very high, eg 5.0+
it seems to go away... eg everything is reflective.
but then again it does'nt look ok anymore due to the glass being a mirror everywhere instead of propper glass...

greetz,
radiance

This is correct, at high IOR, a dielectric becomes very reflective at all angles.

Ok.. spent a little bit of time debugging this issue.
As far as I can tell, it's due to some windows having normals facing the wrong way. The entry and exit IORs were switched, and total internal reflection was causing the reflected fraction to be 1.0, as opposed to something like 0.1 which it should be.

So for glass, the normals *have* to be facing the right way (outwards), on both sides of the pane of glass.

btw, in the top image, the green circled windows have the correct amount of reflection I think.

Hi all!!!
A question: for glass window and to have a right reflections, can we use a plane with normal out or it's obligatory use a cube object with normals out?

Thanks!

I guess you'll have to use a cube for a window. Otherwise it would look like the whole house was filled with glass, because the lightrays never get "out" of the glass again.

Thank you Debris,
now I understand because my windows doesn't reflect anything also with IOR >2.0.