So this is what i am trying to make and i have a white plane behind the glass material and everything looks fine! But as soon as i remove the plane from the background, everything goes dark and even my glass shader looks weird! it almost looks like a mirror and it loses the transparency (alpha channel).
It certainly looks like it’s thinking of the metal object as a light-source and showing you light that’s bouncing off the inside of the glass tube.
I normally treat “glass” and such using compositing techniques – trying for “good enough.” I would treat the metal tube and the glass separately, and the reflection from the glass third, and the shadow cast by the combined object fourth. Then composite the whole thing together. Approaches that try to be “physically correct” are too uncertain and take too long to come up with the wrong thing. But, if I can come up with isolated pieces of what the light appears to be doing in the scene, I can then combine them precisely.
Now, I’m not doing something that anyone’s going to be staring-at for hours and analyzing …
Thank you for your reply! but why would it think that the metal object is a light source? the material on that is pretty simple and there is no emission shader or light emitting object on the scene! also the whole treating them separately got me a bit confused! this is a pretty simple setup and i have no idea why everything get messed up by just removing 1 plane object from the background! Not even sure why the glass only works normal with the plane object behind it…
First post says transparent background, and one option to do it is to make a fake glass. Transparent and glossy mixed with fresnel would include just the reflections. Background plane set as shadow catcher to get transparent shadows.