topic Re: MASH how would one create a growing group of cells on a flat surface in Maya Dynamics Forum

MASH how would one create a growing group of cells on a flat surface

sulkybunny — Mon, 09 Apr 2018 10:24:07 GMT

i am trying to create a cell growth animation. starts with 1 and a whole community grows from the same point..

tried volume point distribution animating the amount... but struggling to get the cells to stay flat on a surface (obviously after adding dynamics to calculate collisions they pile on top of each other.. )

tried all sorts of things.. constraints.. the problem is that the next cell is generated it pushes the previous one in a random direction..

any ideas?

Re: MASH how would one create a growing group of cells on a flat surface

mspeer — Mon, 09 Apr 2018 11:03:39 GMT

Hi!

Distribute on a mesh (plane), then animate visibility with an animated texture.

Re: MASH how would one create a growing group of cells on a flat surface

sulkybunny — Mon, 09 Apr 2018 11:08:20 GMT

interesting idea.. didn’t think about that one.. my new cells are growing into a group of existing cells (should have mentioned it!! 🙂 ) so they need to push the old ones away (like cancer cells) i wonder if this technic will still push the old ones dynamically.. i am trying to simulate growth of cancer cells into a healthy group of cells.. and am after that nice dynamic reactions and moments..

ill give this idea a go any way! thanks 🙂

Re: MASH how would one create a growing group of cells on a flat surface

djonesuk — Mon, 09 Apr 2018 15:18:13 GMT

Have you looked into the MASH World node? It can do automatic collision separation.

Here I used 2 points per cluster and animated a volume point distribution from 1-50 points.

Re: MASH how would one create a growing group of cells on a flat surface

sulkybunny — Mon, 09 Apr 2018 16:54:50 GMT

thanks man...

i tried world.. my main issue with it is that every new cluster is in a completely different position.. creates a sort of noise ... one can't follow whats going on.. if you know what i mean..

so far my best results are to press those cells between two colliders.. floor and ceiling.. so they stay flat.. u can see in my video that ur eye can nicely follow what happens so it doesn't turn noisy like the world node... how ever.. it feels like a cheat.. i would love to find way to stick those cells to any surface.. i was hoping a sort of constraint will work.. still thinking about it.. i tried closest point on mesh from offset node.. but dynamics ignore it... i would love to be able to replicate this on a curved wall or un even surface..

Screencast will be displayed here after you click Post.

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Re: MASH how would one create a growing group of cells on a flat surface

Anonymous — Wed, 11 Apr 2018 15:20:34 GMT

This might get you a little closer. Scene attached (Maya 2018.2)

Using your idea of a Volume > Point Distribution with a sandwich to control the cells.

All I've really added is the idea of MASH Bias. MASH Bias is a way to determine whether MASH or Bullet is in charge. On the Dynamics node if you set this to 100 (play with the value - it can go above 100) it puts MASH 'in charge' (a value of 0 means Bullet is in charge). You can use it as a switch to turn Dynamics on half way through sims. Some examples here - https://www.mainframe.co.uk/bash (there's a link to download scene files)

You could use the Ray Cast feature on the Offset node (new in 2018.2) but you'll find some points may sometimes jump up on top of the others.

Hope that helps?

Chris

Re: MASH how would one create a growing group of cells on a flat surface

Anonymous — Wed, 11 Apr 2018 16:12:48 GMT

Or...just thinking about this again...you could go even simpler and just use a radialField?

Drop the Offset, set MASH Bias back to 0

Create a radialField (Fields/Solvers > Create > Radial)

Set it to say -10 Magnitude

Drag that into the Fields section on the MASH Dynamics node.

That will prevent some of the noise you sometimes get with MASH Bias.

Re: MASH how would one create a growing group of cells on a flat surface

sulkybunny — Wed, 11 Apr 2018 17:40:30 GMT

Thanks a lot Chris i will check this carefully

when u say ray cast.. do u mean the closest point on surface option on the offset node? i tried it but the dynamics seems to ignore it.. the best i could do was the cells stuck to the surface but then drifted off... how ever.. maybe a combination of the Bias (which i was aware of) and the radial force (which i didn't think about and sounds like a great idea ) i do have two MASH networks interacting.. (one existing cells and the other growing...) ill see how they both react to this force..

thanks 🙂

Re: MASH how would one create a growing group of cells on a flat surface

Anonymous — Wed, 11 Apr 2018 17:52:09 GMT

Yep, Ray Cast is new in 2018.2 under the Closest Point on Mesh settings but
that method will only work in combination with a bit of MASH Bias.

The Radial Field set up is definitely my favourite visually but that's
dependent on the final result you're after of course 😉 The other nice
thing about it is it should work on uneven surfaces too assuming you can
position it so the field's force pulls in the right direction for your
surface.

Re: MASH how would one create a growing group of cells on a flat surface

sulkybunny — Wed, 11 Apr 2018 19:31:07 GMT

hi Chris

only the flight node seem to have a field section... can one hook up any dynamics sim to a force field?

Re: MASH how would one create a growing group of cells on a flat surface

sulkybunny — Thu, 12 Apr 2018 05:42:26 GMT

Hey Chris. i agree the radial force is an elegant solution.. its a pity you can't control which mash network it effects... as i have one very tidy grid of cells - network 01 (healthy cells) and one growing Network 02.. my worry is that the field will pull in the grid and get it out of alignment.. i will defo give it a go. maybe the collision will keep the grid somehow steady..

what MASH should really have is a "make soft" node... imagine controlling which parts of the network are soft with a fall off object!!

Re: MASH how would one create a growing group of cells on a flat surface

Anonymous — Thu, 12 Apr 2018 08:50:15 GMT

Does your second network (grid) need to be dynamic? If not, you could just use the ReproMesh of your grid network as a collider (you'll need to be in Repro (mesh) mode and not the instancer for the grid network).

Re: MASH how would one create a growing group of cells on a flat surface

sulkybunny — Thu, 12 Apr 2018 08:54:09 GMT

Yeah the grid has to be dynamic as it’s disturbed by the growth... you know .. the area around the growth shuffle and move away..

The best results I get so far is the sandwich method 🙂 on vertical surface I just turn off gravity .. and bringing down max velocity on mash make it all kind of stay ..

I wish there was a “sticky” attribute .. like N particles

Re: MASH how would one create a growing group of cells on a flat surface

Anonymous — Thu, 12 Apr 2018 08:55:52 GMT

A bit of MASH Bias on your grid might help with that too.

Re: MASH how would one create a growing group of cells on a flat surface

djonesuk — Thu, 12 Apr 2018 14:15:14 GMT

Just a point of clarification, the fields section is on the BulletSolver not on the Dynamics node.

Re: MASH how would one create a growing group of cells on a flat surface

Anonymous — Thu, 12 Apr 2018 14:57:11 GMT

Typo but I can't seem to edit my post. Good spot 😉