Shadow not in render

[bjoern_degroote]

Hello, i have some problems with the mtlwrapper. I use a domelight with a hdri map and a simple plane. I
t will not render correct, the plane is only black.
I use Vray 5 Update 2.2 . What i am doing wrong?

[fixeighted]

Set the 'alpha contribution' to -1.0 and you will need your dome light to be invisible also

[caypiranha]

you set "matte surface". So whats the background on that? May you try to set Alpha Contribution to -1 and ckeck your alpha. shadows are now being set there. in the moment the whole plane will appear white and there is no sense on that so far and as I know.

[bjoern_degroote]

Hello thanks for your help. I just set the dome light to invisble and the Alpha Contribution to -1. No difference in the render.

I need this plane to have a shadow on a transparent background.

[caypiranha]

but you checked your alpha? The render itself shows of course no difference. Use a simple light instead for checking the technique. if that´s clear, get a dome light. vRay won't render "transparency" like the small checkers in photoshop for instance. you have to do it in your comp program

[bjoern_degroote]

Just checked the alpha, you are right. Its only a viewport "problem"