VRay 3.6/Maya - Correct way to get alphas when using the dome light (with a transparent object)?

Hey guys - I’m sure this is simple and I’ve searched but haven’t *quite* found the solution.

I’m using the Dome Light and an HDRI map to light a clear acrylic plastic trophy.

Looks great until I realize I can’t get an alpha channel.

If I go to the dome light and uncheck alpha it gets me an alpha around the object, but not for any of it’s transparency.

If I go to the material and check “color + alpha” under the reflection options, it gets me closer. But it doens’t feel quite right.

I’m fairly novice when it comes to VRay so I’m sure i’m just overlooking it. I just figure when I make my object transparent it will automatically apply to the alpha. Not so apparently!

set the dome light to invisible (under options)? Is that what you are after?

Thanks for the reply, but nope. And I actually had that in an earlier draft of my message but apparently left it out, doh!

If I do that, it just basically turns off the dome light and still blocks/fills the whole alpha.

you mentioned you changed reflection to color and alpha, did you change the refraction to all channels?