Particle Mix Animation

[MaverickMongoose]

Hi again Dr Sassi, quick question,

with the particle system in C4D, is there a way to have the particles try to return to their original positions after being pushed away? Similar to what Mix Animation would do to lLoth or Folow Position would do to Rigid Bodies?

I'm trying to create this effect https://www.instagram.com/reel/DOehIU0Egxq

But I cant get it a smooth, its almost liquid like.

Here's my attempt anyway, I couldnt do it with particles alone so I tried to do it with a mix of Rigid Body, but its not so smooth.

https://we.tl/t-Y8oInCCcJL

Im sure theres a particle tool that will do this but I cant find which one.

Thanks again

[Dr. Sassi]

Hi MaverickMongoose,

Going by the video, it feels more like "peas on a plate".
They don't move back to their initial position. They just find a new place using the path of the lowest resistance…

Please have a look here:
CV4_2026_drs_25_PAhs_01.c4d

Does it come close? (Please evaluate the RS Render View). It comes closer to your suspicion of "fluids".

BTW, as a side note to answer the position question: Noseman showed a technique to bring Particles back to a specific position that was recorded at one point. The key idea here is to use the recorded and the current position and define a specific Velocity with it, which moves particles back.
https://www.youtube.com/live/4BXPxcRwVBc?feature=shared&t=717

In a later show (12 days ago), he shared an additional tip to normalize the Velocity created based on such a position pair.
https://www.youtube.com/live/MHZ5R3HfwWg?feature=shared&t=2597

Enjoy

[MaverickMongoose]

Gunius! That works great, thanks for that, again I never would have thought of that!

One quick question though, I've tried to recreate this but I've noticed the particles are intersecting. Especially around the edges of the heart shape as you can see from the attached screenshots from your project file (Seen in the closeup too).

Is there a way to increase the accuracy of paricle interactions without using rigid body which will remove the liquid look? I tried increasing substeps and collision passes, iterations, but it doesnt seem to have any effect on the particles.

Screenshots: https://we.tl/t-7uEgI9516A

Thanks again

[Dr. Sassi]

Hi MaverickMongoose,

Thanks for the kind feedback!

My best guess, the size of the spheres and the "virtual size" of the Particles are not matching.

Check the Attribute Manager> Mode> Scene> Simulation> Liquid> Default Radius.
This needs to match to avoid this.

To get a more precise resolution, please have a look here
https://help.maxon.net/c4d/2026/en-us/Default.htm#html/OFPLIQUIDFILLEMITTER-FP_LIQUIDFILLEMITTER_MESH.html?TocPath=Simulate%2520Menu%257CThe%2520Simulation%2520System%257CParticle%2520Emitter%257CLiquid%2520Fill%2520Emitter%257C_____3

If you have a Liquify Object working to turn particles into Fluid particles, there is a transition time to avoid "explosions": Ease In
https://help.maxon.net/c4d/2026/en-us/Default.htm#html/OFPLIQUIFY-FP_LIQUIFY_GROUP.html#FP_LIQUIFY_CONSTRAINTS_EASEIN

To get finer borders, use smaller spheres, or render on with Particles and one with Liquid Mesh, then Blend both, whereby the Mesh would be dull-black, and the spheres a little bit more telling about the light setup on their surface.

All the best

[MaverickMongoose]

Thanks again for that, I played around with the particle sizes and ended up scaling up the whole scene which kind of fixed it.

But one thing I cant seem to fix is some particles randomly popping and shaking up and down.

It must be a sim quality setting or something but again, no matter what I try it wont stop shaking.

Here's my file and a video showing the problem, any ideas? So close to finishing this one!

https://we.tl/t-4ezMdO6nuc

[Dr. Sassi]

Hi MaverickMongoose,

This is an interesting question, and besides a higher
Attribute Manager> Mode> Scene> Simulation> Liquids> Surface Tension Iteration
I have found no option to change that, whereby I would suggest this option, as it changes a lot of the shape.

From my perspective, Fluid Particles are not trying to collide and bounce off each other; it is a more complex interaction among all of them, which leads to a connectiveness, while losing but also showing viscosity as a result. Simplyfied, the particles surrounded by others create a balance among all of those "relations (or forces). On the border, this balance is not given, and border particles tend to come closer here. Since this creates for the Fluid Mesh a nicer edge to work with, I suppose very little has been explored to define it otherwise. Hence, my suggestion is to keep it smaller.

Your example was a black heart, and following it made this a nearly invisible part. I understand that you either need the light in that way, or have placed it to put the effect into the forefront of the visuals.

I have nothing that would remedy it other than to avoid putting the spheres so clearly readable. If that is needed, you might try to use Ridid Body options and spheres.

Cheers