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Garret Walter avatar image
Garret Walter asked ·

Houdini VDB fireball in C4DtoA

I've been feeling for awhile I'm doing some wrong when trying to render blackbody flames in C4DtoA. I've been working on a shot with 2 fireballs. I rendered out VDBs from Houdini but when I try and render in C4D the temperature VDBs seem to be way to high I end up getting these wayyyy to blown out values. Check out the attached images.

If I really lower the emission or intensity values I can end up getting the flames less blown out, but then I lose tons of details that I want to see. I've tried putting on a volume_sample_float to map my values better but it still seems to lose a ton of detail.

It seems like my temperature values are always super crushed in the very high end instead of being more evenly distributed and I'm struggling in finding a way to remap them.

I also included a second image that shows lowering the temperature significantly but also shows how much detail I end up losing.

Does anyone have any advice on how they set these up? Thanks.

c4dtoahoudinivolumetricsvdb
screen-shot-2018-08-28-at-105919-am.png (73.5 KiB)
screen-shot-2018-08-28-at-110316-am.png (143.7 KiB)
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Garret Walter avatar image
Garret Walter answered ·

I haven't tested it in HtoA, but I can get good results with Mantra. Interestingly it's almost entirely opposite compared to C4DtoA volume render. In Houdini I have to push the intensity quite a bit, in C4DtoA I have to turn the intensity down super low, to something like .001 in many cases to get anything even remotely similar.

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Peter Horvath avatar image
Peter Horvath answered ·

Maybe it' something to do with scaling, I'm not sure. Does the render look correct if you render from Houdini with HtoA?

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