Bacteria

[breadbox]

how to make an effect such as this one?

its pretty tricky if you look closely at what happens. the bacteria splits sort of from the center and bumps around each other bacteria.

was thinking of making particles that collide, and using some kind of grouping rules to metaball select particles together.

any ideas about this effect?

[breadbox]

I had an idea. i made a picture of it.

so in the diagram we have a single point emitter and particles in a line release. they will be subject to an if then loop so that we can determine how many particles and group them or divide into 2 groups accordingly. each group gets a metaball mesher on it that is exclusive to its points in the group.

so from the emitter we immediately create a group of particles 'group red' then we do an IF loop on the red group. We would be checking to see how many points we have and if we have over a certain amount say 10 points the red group we would divide by 2 and then create a new group and move the end points into a new group and keep the new particles close to the emitter in the red group.

then we repeat the If then loop on the red group this time. I can see maybe the math making more sense if we reverse the point order so the newest points are the ones that just emmited but this is the basic idea. im not sure exactly how to write the expression in the group node in houdini any thoughts?

also if we could create a siimple collider for the particles so like in maya nparticle basically a radius that is the same size as the metaball radius we could cheeply simulate the spline worms bumping into one another?

[ehsan parizi]

this looks very complicated! I mean if you wanna make the exact same effect! because the way they collide, is really complex! anyway, I was thinking maybe a combination of L-System and polywire node, base on $CR might work, but it doesn't look that dynamic! you will be able to get that splitting effect perfectly ( which I don't think you can, with metaballs! and even if you can metaballs make your scene very heavy!) but still the collision effect remains a problem!

[pclaes]

I would do this with a sopsolver and pointcloud lookup. Pushing points away from each other iteratively. I think the tricky bit is to make sure they stay together as lines rather than circles. So you will probably want to identify a head and a tail within those five points and find a way to align the other points inbetween. Perhaps it could be done by building polygons (lines) out of every five pieces and ensuring the angle between connecting neighbours are always less then 10 degrees (these polygon lines are just there to get to the neighbour in vops and act as constraints). That way they can bend a little.

The splitting is branching off and duplicating points after a certain time interval. It is very similar to a particle system. If you add attributes for parent and child, you could probably even establish a hierarchy to see which bacteria originated from which parent.

[breadbox]

thanks for the help.. at this point im going to have to keep going over the basics in houdini... a bit over my head. maybe in a few months ill get there.