hello, I come back to this subject because it seems that there is still no solution found...I admit that I do not quite understand that you are not developing a credible alternative to be able to use any photograph in background with the management of reflection and refraction (as with vray and the "light material" which works perfectly..). For a rendering engine dedicated specifically to architectural representation, I find these limitations very annoying.
I know that these limitations have been known for a long time but I am surprised that you still cannot find a satisfactory solution.
Do you have any views on this?
Thanks a lot
Mienda
Corona is a highly phsycally-based renderer and does not tolerate un-physical effects as well as some other renderers do (including V-Ray, which is more flexible in this regard). In real life, you cannot have an object which is visible directly, but does not affect lighting in any way. That's why it's problematic for Corona. We have this issue logged and it is acknowledged by our developers, but it is possible that finding the right solution requires careful planning and time to make sure that other parts of the renderer do not get broken. It is possible, that fixing this single issue would mean re-writing half of Corona core and would introduce many unexpected side-effects.
On the other hand, I agree that the ability to use background plates, which would be visible only directly, is an expected feature (similar to rayswitchers, shadowcatchers, etc).
One workaround for now would be to try making scenes as physically-correct as possible, meaning using real geometry instead of background plates, or replacing the background in post-production.
