Can't get Embergen VDB shading right AT ALL...

Fri May 23, 2025 8:39 am

Hi there,

For an important theater show I must render a dragon spitting fire simulation,
I have a part of the .VDB here :
julienbach.de/files/SpitFire.7z

But I can't get the shading right, I did many tuts embergen/octane,
and i never get the nice shading, i just get ugly overburned stuff and crazy extreme gradient values to get anything its depressing...

I just need it to look like good normal basic flames with a little bit of smoke like the embergen viewport here :
julienbach.de/files/SpitFire04.mp4

Can someone help me and try and if you get something close to send me the material ?!
That'd be super helpful, im stuck with a very bad look and my deadline is close

Beppe OctaneRender™ Italia Blue Sky · Fri May 23, 2025 10:03 am

Hi,
please try with this version, and play with max Value in Volume Gradient node in Emission, and with Scatter value, to have more or less smoke:

SpitFire_b.zip: (31.79 KiB) Downloaded 51 times

ciao,
Beppe

Fri May 23, 2025 12:00 pm

Thank you Beppe for your quick reaction !
At least something thats looks like a fire shows up in the viewport...
Now I can't get it the other way around, like in the embergen example : its currently the aged part of the fire that gets emissive where it should be smoke, and its the young part that shouldbe flame-ish that looks like smoke...
Can't get it around by flipping the gradient... What a mess that thing is its driving me crazy >.<
By any chance, can you have something that just look like a normal flaming stream and not like some gaz explosion ?! (like in the embergen example ??
Im sorry but i've been trying hard for some time and just never got anything better these settings are really counter intuitive.

Fri May 23, 2025 1:58 pm

The unsatisfactory results seem to be missing from the post (not attached as image files). It would be helpful to view these render outputs.

The demonstrations on this Octane VDB page is utilizing Embergen free demo files for the Pyro section, however it's not the same data set.

There are some "tips" that may be helpful or may not be of any aid.

Fri May 23, 2025 2:51 pm

[Removed duplicate]

Fri May 23, 2025 2:59 pm

Look 04, with "smoke" and a different frame (0100)

Path tracing kernel, high enough Scatter Depth, AgX Punchy are some of the most important settings.

Material group (ORBX "as code"):

Code: Select all

<?xml version='1.0' encoding='utf-8'?>
<OCS2 version='14020000'>
 <graph id='1' type='1' name='clipboard'>
  <graph id='3308' type='1' name='vdb-shading-look-04' position='424.25 -2'>
   <attr name='color' type='8'>1 1 1</attr>
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    <attr name='compatibilityVersion' type='2'>13000200</attr>
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Fri May 23, 2025 3:27 pm

Alright,
so see in the picture here ,
whatever how i play with emissive gradient, it affects the tail, the smoke part...

I neet the blowtorch to be like fire, like this :

and its just immossible to get anything near...
what do I get wrong ?!

Fri May 23, 2025 3:45 pm

Here's a slightly tweaked version, closed to the reference. Render viewport (Standalone 2025) and ORBX code material group attached.

The key is in the ramps, provided that the rest is accordingly set and in place. Values may be off (no context) but can be proportionally tweaked according to the project file.

ORBX of the whole demo project file can be made available if necessary.

Code: Select all

<?xml version='1.0' encoding='utf-8'?>
<OCS2 version='14020000'>
 <graph id='1' type='1' name='clipboard'>
  <graph id='100' type='1' name='vdb-shading-look-05' position='527.25 88'>
   <attr name='color' type='8'>1 1 1</attr>
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      <attr name='value' type='8'>0.175 0 0</attr>
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      <attr name='value' type='8'>2.5 0 0</attr>
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      <attr name='value' type='8'>1 0 0</attr>
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Fri May 23, 2025 3:47 pm

If copying the ORBX does not result in similar or identical results, it may be the VDB import parameters (default in Standalone, with all three loaded: density, flames, temperature).

Sat May 24, 2025 1:22 pm

Allright,
thanks for the effort !
But these are all too smokey and not flamey , especially at the source...
This effect is important to get right,
at the end I tried with redshift and (unfortunately) got a much closer look... without headache.
it still sucks compared to the Embergen sim though...
http://julienbach.de/files/DragonSpitFire_POV9_01.mp4