Houdini Bacteria Growth

[gramx]

Hi

 

Has anyone got any ideas on how to create multiplying bacteria growth in Houdini like in this video clip:- 

 

Thanks

 

Graham

[TheDude]

You might be able to do something simple along these lines with a simple particle. Start with single point, then in a solver, emit npoint ( ) so that it emits 1 particle per 1 particle. to make them spread you could take the pointcloud of surrounding positions, merge that and length them, and then force the position of each particle in the opposite direction so they spread. Per particle emitted in the solver you could add an attribute ID, then add in 2 particles either side of it (to create the appearance of them being long and wrapping them in a foreach, which could get real sloppy) or fluid wrap the entire thing. This way you may even fake some sort of grow/split of them. Just throwing out an idea, it'll be much harder than this though once you get down to some nitty gritty I'm sure

[Skybar]

Maybe could be done with a wire sim or even FEM? Make a line grow, and once it reaches X length, split it in two. Then those two keep growing, eventually gets cut in half as well and then you get that exponential growth. Just an idea.

[gramx]

Thanks for the help!! Some interesting ideas. The client has actually agreed for a much simpler animation now, but I will still have a play around for fun! Thanks again.

[eetu]

It's a bit simpler, but you might get some ideas from this thread http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=31855

[gramx]

That's really cool!!!! Thanks for link!

[Artem Smirnov]

Hi. I've found this problem quite interesting. So after couple hours of playing I came up with something like this=) It is not exactly the same as in example video but look pretty similar.

 

http://vimeo.com/101713600

[gramx]

Very cool Artem, I like it! Have you a brief explanation on the setup? Thanks

[Artem Smirnov]

I have used custom verlet solver implemented with HDK. It is very similar to solver in "Simple Cloth" example file, so you can reproduce it. 

 

Maybe could be done with a wire sim or even FEM? Make a line grow, and once it reaches X length, split it in two. Then those two keep growing, eventually gets cut in half as well and then you get that exponential growth. Just an idea.

That is the basic idea. I refine lines somewhere near the midle. In case of new point beeng too close to any old point, the strain on the edge become too high and it is tearing, spliting the line to pieces. And so on...Hope my english is understandable enough=)

Edited July 25, 2014 by Artem Smirnov

[sergio]

I have used custom verlet solver implemented with HDK. It is very similar to solver in "Simple Cloth" example file, so you can reproduce it. 

 

That is the basic idea. I refine lines somewhere near the midle. In case of new point beeng too close to any old point, the strain on the edge become too high and it is tearing, spliting the line to pieces. And so on...Hope my english is understandable enough=)

Hi Artem, i would like to take an approach to verlet integration and hopefully come to a solver like yours but can't find that simple cloth example anywhere. Is it an hdk example file from previous houdini versions? If you have it lying anywhere on your drive could you please upload here. Thanks in advance.

[Artem Smirnov]

Hello, Sergio. As you might know, things are getting better with every release of houdini.) Verlet integration is just another word for position based physics, so now we have this kind of solver implemented by sesi in houdini 14 grain solver. You can do exactly what I have done  with pbd, constraints and couple of lines in wrangle nodes)

[sergio]

Thanks Artem i will take an approach in pbd.