I have a problem with the transparency shader. I need to use it combined with the glossy one, mixing using a fresnel factor. Unfortunately I keep getting the same result...an annoying black area. ON the other hand, with Holdout shader everything seems to work correctly. I'm attaching 4 screenshots that I hope will explain better the issue.
I've already seen a discussion about this theme:
"How to render semi-transparent objects with transparent background as a png with cycles"
but it's two years old and I don't know if something has changed in the meantime.
And all this, because I need to resolve an issue that I have in a scene. I have a big surface made of glass, that is in front of all, this surface affects to much the render time and the level of noise.
Is there some sort of trick to resolve that problem? I have already play with light path, but nothing seems to work. I think that the noise is caused by the refraction properties of the glass shader. Can someone help me?