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VDB Pheonix density

Unread postPosted: Fri Jun 21, 2019 11:06 am
by dane
Hey guys,

I'm early stages of simming and I've got a VDB cache from Pheonix/Maya that I'm trying to shade and render in Clarisse.

Channels included are:

Temperature
Smoke (I'm guessing this is density?)
Velocity
Fuel

I can get things looking generally correct using the extract property node and whatnot but I cant seem to map the density correctly to get a falloff at the edges, it seems to clip at the bounding box:

smokeClip.png


If someone wants to play with the cache and advise you can down it here:

https://wetransfer.com/downloads/7e2081 ... 939/9f0191

Thanks for any advice,

Dan

Re: VDB Pheonix density

Unread postPosted: Sat Jun 22, 2019 3:22 pm
by mdkai
Hi
testing the VDB there is nothing wrong with. Phoenix is using the Smoke parameter for the density so thats correct.
As for the file, just add a scope element and place it so that the gradient will remove the upper density.

It would be required to have enough space for the sim to fade out it's smoke value at the top. Just re-sim and leave the top fade out naturally.

Cheers
Kai

Re: VDB Pheonix density

Unread postPosted: Wed Jun 26, 2019 2:17 pm
by dane
Its not that the sim is getting stopped at the top it open and getting clipped off. What I need to do is reduce just the smoke leaving the flames how they are, usually you'd control the density with a curve or drive it with the temperature and control that but whatever I seem to try doesnt work. A gradient for instance just seems to be outputting a single value and not a ramp based on the extract property input.

Re: VDB Pheonix density

Unread postPosted: Wed Jun 26, 2019 3:14 pm
by dboude
Hi Dane,

That's what you want ?

Image

I used the temperature remapped to drive the density multiplier of the volume material.

VDB_dane.project
(60.19 KiB) Downloaded 14 times


Cheers

Re: VDB Pheonix density

Unread postPosted: Wed Jun 26, 2019 3:34 pm
by dane
This here is effecting the flame density also, I did some testing with a VDB from houdini and that seems fine, I think its something Pheonix related annoyingly, the way they handle their channels is a little weird. Dont worry but thanks for your help.

Best,

Dan

Re: VDB Pheonix density

Unread postPosted: Wed Jun 26, 2019 3:42 pm
by dboude
Ok, cool that you found a solution ;)

Cheers !