VrayMtl Alpha Transparency

#1

Hey folks. This is blowing my mind.

A glass material, with a certain amount of transparency should come out in a greytone in alpha. This is not the first time I am rendering out alpha´s with transparency but this time it makes me crazy. I either get an almost black or a pure white Alpha.
In this specific case with the images the alpha comes out with a value of 4/4/4 in RGB even though the transparency amount is at 0.5! And it would not matter if I put pure white refraction color and .5 for amount or 1 for amount and .5 for color. The result is the same and the alpha does not look, how I expect it.
Am I missing something here? Affect Channels is set to color and alpha. But I am out of answers and would be so glad if anyone could help out here.

Here are some exampels of my simple setup.

#2

And this is how I would expect an alpha for a material which has a transparency of .5 (MRay)

#3

Just wanted to inform you guys, that this issue has been treated as a bug by chaos group.
The problem was that I did put the diffuse color!!! ( not the refraction color) to black (000). But when you change it to like 0.01 the problem disappears and the alpha´s come out like they should be.

#4

Thanks for the workaround, what is annoying is this bug has existed for a very long time with no resolution or fix - so now there is a workaround it is nice to know. Thanks for sharing it.

#5

Everything works fine here, Below CylinderOpc=1 & SphereOpc=0.5
Give me ur scene file.

#6

@ruchitinfushion its not about the “opacity” in the basic parameters. What I mean is create a similar scene like mine at the first posting. Its the alpha of transparent, refractive objects and what they show whats behind them.
I know that you usally should not use complete black or complete white values for (almost) anything. I thought this does not count for diffuse color on a transparaent material. That seems to be buggy.

@Hamburger I thought I am the only one noticing this. Glad that I could help with this.