VolumeGrid with FadeOut other then zero, disappears in batch rendering

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Hi,

we need help again: using Maya 2020.2 (Windows 10) with V-Ray 4.3.004.

A simple scene with a VolumeGrid loading some Houdini vbd-files and a FadeOut value of 50 or 100 (seems anything other then zero does not work) renders fine within Maya. But when we render it via one of our render node by a simple batchscript, the VolumeGrid just disappears. With FadeOut = zero, the VolumeGrid is back again!

Any trick to prevent this behavior? We can’t render several 4K scenes within Maya.

Thanks for any hint.
Lars

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Update: The VolumeGruid Effect does not completely disappear, it just disappears from the alpha channel and the MaterialID. As I have used PDA player the image was shown with premultiplied mask enabled and though I thought that the VolumeGrid has been disappear.

We tried to switch to Volumetric Geometry mode + set Scattering to Ray-traced, but that only leads to a complete disappearing of the VolumeGrid.

Strange (at least for us) is that the other scenes with FadeOut = 0 render fine with Alpha and MaterialID.

Thanks for any help and please forgive us our ignorance - the VolumeGrid is a new terrain for us.

[hermit.crab]

From what I tested it seems to be working fine. The Fade Out parameter works as feathering, so it should be normal to expect a less visible alpha. Note that the Material ID render element is not supported, hence the lack of result (list of supported render elements). You may try using the Render ID or Object ID (Volumetric Geometry mode is a prerequisite; an object id attribute is needed to the VolumeGrid node) passes as a workaround. If you are certain that the alpha results differ, do attach the scene here so we can take a look.

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Thanks Aleksandar. Can you please take a look at the attached scene? The Fade Out is zero and the RGB looks fine, but the Alpha is pur black?

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Sorry, forgot the vdv-files. Here is the one for frame 1000.

[hermit.crab]

Thank you for the provided files. The issue is neither Fade Out nor batch rendering related (it is present in Maya as well). The lack of alpha is caused by the 'Fully Visible' fire opacity mode of the VolumeGrid (Rendering>Fire). This mode means that fire will always render as if it has full opacity, but will not produce alpha. Set the mode to use its own or the smoke's opacity to get information in the alpha channel.

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Thanks a lot! That is the solution we searched for. Great!