Mental ray Bifrost alpha completely solid

[Anonymous]

I'm having a problem where, when I render my bifrost mesh with the bifrost shader, the alpha is completely solid, no matter how much transparency is on the mesh. Has anyone run into this problem?

[mspeer]

Hi!

Try setting Index of Refraction to 1.

[Anonymous]

My refraction is already set to 1.33. Unfortunately that isn't effecting the alpha. At this point I've just decided to fake it in comp with a combination of refraction and reflection passes and using some luma mattes from the beauty pass. 

[mspeer]

Hi!

There is a big difference between 1.00 and 1.33 .

Glad you find a solution that works for you.

[Anonymous]

1.33 is the refraction of water though. I did change it to 1.00 just to see, and it still didn't work.

[mspeer]

Hi!

Because of multiple refractions and reflections of an object it's not uncommon that the whole object get's full white in alpha channel, even if the rendered pixels in the color channel are black.

Using different render layers is the best way to handle this for compositing.

Just to show, here are my results for settings of 1.0 and 1.333