Rolling thick smoke simulation

Hi Everybody,

I am new to this forum, nice to meet you!

I am very interested in the simulation possibilities of Blender. I have been using Flip fluids with a lot of joy!

Now I was inspired by a new commercial of Nespresso, they have an animation of smoke engulfing some nespresso cups. What I like a lot about this smoke is the detail that is envolved but also the thick silky smooth look and feel to it.

nespresso commercial link

I have been trying to get something like that in Blender. I am using a smoke flow object with negative temperature difference and have it fall over a floor object (collision) and have some spheres that are also collision objects. I have a basic principled volume shader with a density of 100. This is a very basic setup of course and doesn’t come close to what I am looking for.

Does anybody has any tips on how to get a bit closer to the nespresso commercial look?

This is one of my first test renders, but I already was noticing the smoke doesn’t come close to the look I am after.

Thank you!

Welcome on BA !

Come on, your render is green, on Nespresso it’s brown ! Are you colorblind ? :joy: Ahahah just joking :joy:

Having a look on this :

I would say main difference between your render and Nespresso’s is the way the shader goes from “smoke” to “nothing”. You know, when setting the shader, you should use the “density” info, it will make you able (with a color ramp for example) to choose the “Threshold” of the density

Comparing the thing to an image mask : your limit is too blury, whereas on Nespresso’s it’s a sharp edge.
You :
Nespresso :
Choosing how hard and quick the shader goes from smoke to nothing will change everything :slight_smile:

See you :slight_smile: ++

Hi Tricotou,

Thank you for the reply! You are totally correct about the limit being to blurry. I tried to do different density within the principled volume shader, but if you go to high, you will get these weird banding effects.

You know, when setting the shader, you should use the “density” info, it will make you able (with a color ramp for example) to choose the “Threshold” of the density

Also the material in the nespresso commercial seems to have a subtle difference between darker grey and lighter greys. I don’t know for sure if this has to do with the lighting, absorption or some other reason, but probably I have to use the color attribute for this?

No idea how to do this, but I will dive into this.

Kind regards, Patrick

Two things that are in general a good idea to get volume scatter shaders to behave more nicely:

  • in material settings, set Volume->Interpolation to cubic
  • in render settings, set Light Paths->Max Bounces->Volume to 3 or higher.
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Hi Omgold,

Thanks for the tips. I already had max bounces up to 5, but I didn’t know about the interpolation. Now I do not have the banding effect.

But I have been looking into the threshold of the density, but I cannot find out how to control this. I have this setup, but doesn’t do much.

Is this the way to do it?

Almost, except for setting up the color ramp differently. To get a sharper transistion between the regions of smoke/no smoke, you need to set both color stops to nonzero values close to one another. Depending on the absolute density of the smoke, you need in adding another multiplier. Something like this:

Thank you, I seem to get somewhere, but I still have the banding issue, even now I am using the interpolation cubic! Still I have the feeling it’s not as sharp as the Nespresso version, but possibly they also used some post processing sharpening? Like what I have seen here: post process sharpening

This is the result so far, of course the setup of the scene and the lighting needs to be improved, this is just a test. Also the smoke has some weird shapes, probably to do with the “high resolution” settings.

I also used the density attribute to have difference in color between the edges and the inner parts of the smoke. Maybe a bit too much right now.

Okay, yes, seems you are making progress. What I notice is these ‘ring’ patterns on the smoke. These are again artifacts from the sim grid, appearing because of the extremely sharp transition. Maybe you are just at the limit of what you can get out of it as this resolution, so a higher might make sense.

Do you mean by weird shapes these or larger-scale the outlines? If it is the latter, well the current smoke is very old, and has difficulties producing realistic turbulence patterns. Mantaflow is much better in this respect (available in a separate branch, and scheduled to be included officially in 2.82).

Hi Omgold,

Thank you for the reply. I will try a higher resolution, is was now at 64 with high resolution at 5. I meant the outlines.

I was actually just looking into the mantaflow branch, maybe I will try that.