How to create particles on surface to simulate cell division or exocytosis

[Anonymous]

Hi all!

I want to animate the surface of a cell covered in spherical particles, and then have some of those particles bud away from the main surface into a separate spherical structure (like in the drawing below). I also need these particles to collide with each other.
I’ve attempted this with Maya’s MASH and also with nparticles, but can’t seem to get the effect to work.
Any ideas would be greatly appreciated!

[sean.heasley]

Hi @Anonymous and welcome to the community!

Something like this should help get you started!

[Anonymous]

Thanks for such a quick reply Sean!

I've tried this, but this gives a blobby continuous surface to the cells, whereas I need them to be covered in small colliding particles. I thought maybe I could attach a particle system to the surface of the cells in that tutorial..but because those cells are made from nparticles themselves, this doesn't seem to work.

Another option I've tried is baking a boolean animation where two cells are coming apart, but in this case the surface geometry keeps changing so much from frame to frame, that when I attach a particle system to that surface, the particles jump around like crazy - also not the effect I'm trying to get.

[sean.heasley]

Hi @Anonymous

Instead of attaching the particles to the other particles (since that wont work) you could either make a plane and attach them to that then just have the plane invisible when you render or you could try parenting the particles to the other particles so while they aren't attached they'll follow them throughout the animation.

[sean.heasley]

Hi @Anonymous

Just wanted to check in to see how things were going. Are you still having this issue?

If your issue is resolved, please click Accept as Solution on the posts that helped you so others in the community can find them easily.

[Anonymous]

Hey Sean,

I'm still trying to find a solution.

I can emit particles from the surface of a plane and hide the plane, but the problem I'm running into is actually animating them. With goals I can control all the particles at once, but I need only some of them to "bud" up off the surface, and the rest of the particles to fill in the gap.

Here's an example (but I want to do this in 3D not 2D): https://gfycat.com/smugwastefulaustraliansilkyterrier

[sean.heasley]

Hi @Anonymous

In that case I'd recommend looking into MASH.

You could assign the particles to a MASH network and then have more control over them that way.

This is basic MASH overview but there's a lot more in depth tutorials out on YouTube and the internet:

[Anonymous]

Thanks! Yeah I tried a few things with MASH, I think the main issue though is you can't have self-collisions between the particles unless you have dynamics applied? Unless I'm wrong.

And with dynamics applied you can't have the particles stick to a surface, no?

[sean.heasley · Accepted solution]

Hi @Anonymous

No you should be able to do that still it just takes some tweaking.

I actually did some digging and found this older thread about cells and MASH.

While it's not exactly what you want, it could help get you started with the base cells on the plane.

[Anonymous]

Oh cool, thanks so much! I'll take a look 🙂