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Bug with Phoenix fire and smoke

Posted: Sat Aug 26, 2023 2:24 pm
by coilbook
Hi,
If I animate phoenix temperature down to where only smoke is visible smoke catches on fire even more

Re: Bug with Phoenix fire and smoke

Posted: Tue Sep 12, 2023 3:14 am
by neonZorglub
coilbook wrote:Hi,
If I animate phoenix temperature down to where only smoke is visible smoke catches on fire even more
Thank you for the scene !
It had me scratch my head a bit !
The problem basically comes from the inverted Volume Ramp texture in the Emission ramp.
The color on the left should be dark, and color on the right the most bright.
Another issue is on the texture emission power; I changed from 10 to 0.01
So the Emiss. scale now works fine:
phoenix_emis_scale_ok.zip
(927.24 KiB) Downloaded 115 times
Note: the temperature values created from Phoenix are quite high, (up to ~2000.0), that's why the emission power should be small..
Hint: we can see the max value of each channel from the Octane Graph viewer, while rendering in Octane viewport, and selecting the Volume node:
for example, on frame 21, there's '131 x 179 x 107, 2509043 voxels, max abs/scat/emis: 1 / 1 / 2000

Thanks

Re: Bug with Phoenix fire and smoke

Posted: Tue Sep 12, 2023 12:53 pm
by coilbook
neonZorglub wrote:
coilbook wrote:Hi,
If I animate phoenix temperature down to where only smoke is visible smoke catches on fire even more
Thank you for the scene !
It had me scratch my head a bit !
The problem basically comes from the inverted Volume Ramp texture in the Emission ramp.
The color on the left should be dark, and color on the right the most bright.
Another issue is on the texture emission power; I changed from 10 to 0.01
So the Emiss. scale now works fine:
phoenix_emis_scale_ok.zip
Note: the temperature values created from Phoenix are quite high, (up to ~2000.0), that's why the emission power should be small..
Hint: we can see the max value of each channel from the Octane Graph viewer, while rendering in Octane viewport, and selecting the Volume node:
for example, on frame 21, there's '131 x 179 x 107, 2509043 voxels, max abs/scat/emis: 1 / 1 / 2000

Thanks
Thank you! Do you guys have any plans to simplify the way octane renders flames? It seems that there are too many repetitive settings in texture emission, ramp emission, and octane volume modifier. Gets confusing

Re: Bug with Phoenix fire and smoke

Posted: Wed Sep 13, 2023 2:32 am
by neonZorglub
coilbook wrote:
neonZorglub wrote:
coilbook wrote:Hi,
If I animate phoenix temperature down to where only smoke is visible smoke catches on fire even more
Thank you for the scene !
It had me scratch my head a bit !
The problem basically comes from the inverted Volume Ramp texture in the Emission ramp.
The color on the left should be dark, and color on the right the most bright.
Another issue is on the texture emission power; I changed from 10 to 0.01
So the Emiss. scale now works fine:
phoenix_emis_scale_ok.zip
Note: the temperature values created from Phoenix are quite high, (up to ~2000.0), that's why the emission power should be small..
Hint: we can see the max value of each channel from the Octane Graph viewer, while rendering in Octane viewport, and selecting the Volume node:
for example, on frame 21, there's '131 x 179 x 107, 2509043 voxels, max abs/scat/emis: 1 / 1 / 2000

Thanks
Thank you! Do you guys have any plans to simplify the way octane renders flames? It seems that there are too many repetitive settings in texture emission, ramp emission, and octane volume modifier. Gets confusing
As for the content of each node, it's designed by the engine team, and there's basically a good reason for each setting, but might be simplified / refactored over time.. For the 3dsMax side, we are planing to make sub textures editable in the object dialog, with also a configurable simplified list of parameters. That will be nice for lights, Phoenix modifiers, as well as all AOVs that can become deep and complex..

Re: Bug with Phoenix fire and smoke

Posted: Thu Oct 26, 2023 9:40 am
by remKa
Hello,

it seems that volume ramp texture has no effect anymore on the look of the fire... and you removed the max grid ?

I'm using Phoenix FD and I find that convincing and nice looking flames are really hard to achieve in Octane, do you have any hint ?

https://www.youtube.com/watch?v=vIclhO2aJ6M