Can Krakatoa render bubbles like this image?


#1

I’ve got a RealFLow sim of bubbles similar to the attached image, but I can’t see how to render the particles in C4D like the attached image. I have searched the documentation, but I don’t see an answer.

Any guidance gratefully received.


#2

Normally, Krakatoa renders each particle as a sub-pixel-sized dot. In other words, Krakatoa particles do not have a size you can control. The idea is that you render thousands of faint dots to achieve results similar to real-world air-burshing where thousands of dots hit the surface and merge into a continuous gradient. However, in Krakatoa they represent volumetric data (Density, Color etc.) at the 3D position, so they can attenuate light, cast shadows on themselves etc.

Bubbles on the other hand usually have various larger sizes and can merge together underwater into blobs. The typical approach for rendering such particles is using a Blob Mesh (a.k.a. Marching Cubes). Thinkbox sells a plugin for 3ds Max called Frost that does that, but we don’t have a C4D version of it.
However, Krakatoa contains some code that can produce somewhat similar results - the Repopulate Particles tag actually creates a grid around the existing particles and seeds new particles around them within the influence radius of each particle, producing a cloud that is very similar to the volume of a Blob Mesh. So on theory you could take a low count RealFlow simulation and use the Repopulate Particles tag to make it look more like what you posted.

The Repopulate Particles tag workflow is discussed here:
thinkboxsoftware.com/kc4d-repopulation/

The following illustration shows a sparse particle cloud being solidified into a blobby-looking Krakatoa rendering:
thinkboxsoftware.com/display … 6258327266

Note that you have no way to control the radius per particle, only globally, so a real Blob Mesh approach using geometry rendering would probably be more flexible.


#3

Bobo,

Many thanks for your prompt and detailed reply!

I will try your suggestion to use repopulation.

best regards, David