Texturing smoke have a significant difference in Eevee and Cycles

Hey guys,

I have simulated a smoke in Mantaflow. How do i achieve the same look as Eevee in cycles?

Cycles:

Eevee:

And on the side im trying to get a holdout material going on for Eevee, isnt going good so far haha

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Wasn’t there something about volume attributes partially unsupported in Eevee?

In any case such a duplicate usage of density (giving quadratic dependence) is a physically incorrect setup. The density input of the principled volume should be a constant. I assume if you try that the result will be closer to the Eevee case (or at least more realistic).

Are you saying i have to add value to density in the pr. volume? without the attribute being multiplied by the a value?

Yeah it kinda have the same effect. Im actually looking for a way to fade the smoke outwards, seems like right now im just stuck with materials.

to do this i added density value which multiplies the fading out partcles as well… and looses the cool details of the smoke :frowning: thats why it looks like a cartoony smoke. I even added a ramp which doesnt do anything, its strange

I meant for physical correctness one should not feed anything at all into the density input of the Principled Volume.

I get, though, what you are trying to do. But the smoke in the Eevee render doesn’t ‘fade out’ smoothly, either, no? Thus I would guess that just tweaking the value of density might give you a similar look.

If you post the blend file, I can take a closer look.

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smoke_BA.blend (700.4 KB) I feel like i have wasted my time adjusting all those parameters, all my settings have disappeared :laughing: mantaflow the domain and flow objects doesnt have them assigned xD

ill stick with internal smoke i guess. So i redid the settings and stuff.

So maybe because the motion is slow that i dont get the details?

Hi.
For Eevee, in render tab > Volumetrics you play with “End” distance starting with not very high values and increasing the value gradually until obtaining a result similar to Cycles.

Edit:
Apparently you did not make any changes to Volumetrics settings for eevee. There you should also enable Volumetric Shadows

Hmm, somehow your file beahves weird for me. I failed to get the smoke sim look like in your images.

In any case, things I noticed:

  • Light Paths -> Max Bounces -> Volume is set to zero. Use something around 2-5 to get some more details.
  • Density is too high. Some you the details probably are from seeing through the smoke at places, so lower density (around 1-10) is likely better.
  • Tweaking the ratio between volume scatter and absorption (the Color attribute on the principled volume shader) can give you more detail in the form of darker and lighter areas.
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Hey @YAFU , I kinda needed the render layer setting on this occasion(the “Holdout” option), so i think i should stick with cycles.

I will try this! thank you! I sensed something weird too.

This will clearly show what im facing right now xD

Any idea with the stretched texture like behavior anyone?

For me it still looks like it doesnt have any details- I upped the resolution there was not much difference.

Indeed odd. Can you try to use a smaller value for Render Properties → Volumes → Step Size?

yeah i reduced it too. maybe because i didnt applyscale for the domain? Ill have to rebake and see :face_with_monocle:

Its a cycles issue. In evee its all fine. @omgold you mentioned about color node. How do you use it? I added the attribute, and how does it really work? i couldnt find anything on this attribute :confused:

Sorry, I didn’t mean the node, I meant the settings of the principled volume to tweak volume scatter vs. volume absorption. There are 3 relevant ones:

  • Density: affects scatter an absoprtion equally
  • Color: affects only scatter (white=maximum scattering, black=no scattering)
  • Absorption Color: affects only absoprtion (white=no absorption, black=maximum absorption)
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Got it, thanks alot!