MTOA VDB worklfow (and alpha issues)

[BigRoy]

Hi, What is the correct workflow to get .vdb files into MTOA. I use the aiVolume and assign an aiStandardVolume shader. This renders fine, but there are some issues with the alpha. Even when the density multiplier (in the shader) is set to 100 the alpha is still not 1 and I can see my HDRI through it, as if added on top. When I gain down my alpha in Fusion I see this:

https://gyazo.com/af8327148bc9f68f07a94e3f9a02a5e1

Alle the vdb's I tested have this issue and I can't reproduce it in V-ray for instance.

Help please! Am I doing somethign wrong here?

[lee_griggs]

This is what I get.

Can you post your scene (without VDB)?

[BigRoy]

Hi, thanks for the quick answer. Are all your alpha values in the white at 1, when you increase density to 100? I had to gamma and gain it down in fusion to make it visible to the naked eye. My values were all in the 0.999-1 range.

[lee_griggs]

Yes, they are just the default values.

[BigRoy]

If you place a bright light behind it do you get this too? Density is up to 100 here

[lee_griggs]

Yes, why do you ask?

[BigRoy]

If i use an HDRI image in a skydome it is visible through the volume.

As I don not get these results with v-ray I was just wondering if this is correct or not.

[lee_griggs]

What is the exposure of the skydome light? Is it the same with all HDRs?

[BigRoy]

The exposure is quite high here (5). Happens with all HDRIs with very bright values.

[BigRoy]

Same setup with vray

[BigRoy]

Any idea what it might be?

[lee_griggs]

Can you upload the MtoA scene and HDRI?

[BigRoy]

Here you go: https://we.tl/uUmkTtYMcg

Thanks.

[BigRoy]

Any luck?

[lee_griggs]

Hi, this is a bug and has been reported. Thanks for your feedback!