2

I would like to have a volume mesh, let's say a sphere, that gets progressively more "misty"

enter image description here

Imagine the mesh being at very high desnity for the top hemisphere, then density becomes lower in the lower hemisphere to the point that it basically transitions to a gas. I want this to be possible to be added to any mesh and control where the lower density happens. I have attempted many ways to achieve this, but controlling the density is not really possible in an arbitary way, only with 3D textures (noise or gradient).

Maik Xhani
  • 53
  • 3
  • Quite interesting ... would you mind to extend your description to be more specific what is your goal visually .... some references (it should be still image or anim) ... why procedural texture doesn't work for you ... Probably any dissolving / disintegration technique like this https://www.youtube.com/watch?v=wm4rDDRcbDQ could work for you? Just instead of spark material you will use something volumetric. – vklidu Apr 03 '22 at 18:42

2 Answers2

4

Until you add more details (mentioned in my comment) ...

One way to dissolve solid into a "gas" can be faked simply by Plane used at the same time as factor for

  • Boolean modifier and
  • Canvas of Dynamic Paint

Boolean operator will handle "disappearing" solid part. Dynamic Paint (with Sphere as a Brush and Plane as Canvas) will generate Weight (Vertex Group) as Fluid Sim > Gas > Inflow.

enter image description here

Added Solidify modifier to the Plane, to avoid glitches of Boolean modifier (even with Exact solver).

Previously I let emit smoke from Particle system (based on DP weight) , but it was somehow unstable for me (it is still included in the file, just disabled).

There can be more ways using just geometry nodes or Particle system, but in cost of less realistic "gas" dissolving.

vklidu
  • 36,165
  • 1
  • 61
  • 135
3

You can try object coordinates with multiple Empties.
Density/spread is controlled by: scaling empties, ColorRamp, Math node > Multiply

High, medium and low density areas enter image description here

Combining three areas, each driven by a separate empty (click to enlarge) enter image description here

jachym michal
  • 31,744
  • 5
  • 55
  • 115
  • 1
    I see, that's a great idea, I will try that out. I wish in the next version of blender we get collection input so that we could get texture coordinate from all the empties at once – Maik Xhani Mar 29 '22 at 13:00