Constraining RBs on a 2D plane and a few other questions

[ch3]

Hi there,

 

I am new to houdini, but I have many years of experience in Maya. I am trying to get my head around the new way of thinking, which is a bit hard in the beggining as houdini is just a massive software.

 

As a learning test, I was to build a system where a group of cubes will attract and collide with each other. But I want the cubes to be constrained to the ground plane (y=0) and they only spin on y axis. It's almost like doing a 2D simulation.

 

I am sure there are many ways to go around this, but my intial thinking was to first create a particle simulation and use it as a goal for each cube. Each particle attracts each other and after balancing forces and drag, I can make them orbit around each other. Using particles, I suppose it's much easier to zero out the y component to turn the simulation in 2 dimensions. Then each RB will have a particle as a goal to follow. As they hit each other they will spin hopefully just on Y axis, but if not I would like to figure out a way to limit the oration to just that.

 

questions:

 

1. How do you make Rigid Bodies follow a point or in this case a particle?

2. I am using a copySOP to create a bunch of cubes under one object. Withint the DOP simulation, how can I see and edit the data for each one of them? Or does each cube needs to exist as an object under /obj?

3. I understand that most of the constraints (and I assume goals) are nodes and work on objects. Is there a way to create all these dynamically and just feed the data straight to the solver? I don't want the total number of cubes to be predetermined.

 

I admit I don't fully understand how you move and manipulate data in houdini, so appologies if I am asking non-sense questions.

 

 

thanks

georgios

[csp]

Hi George, nice to see you here. I will try to answer few of your questions:

 

1. check this recent master class https://vimeo.com/81611332 from Senior mathematician Jeff Lait, in his latest example (I think) demonstrates how to have RBD follow particle and have proper collisions.

 

2. You can use SOP Solver to edit geometry inside DOPs.

 

3. check Houdini 13 Masterclass on Bullet https://vimeo.com/80840429 where Cameron White, among other he covers constraint networks, which allow you to procedurally create or break RBD constraints.

 

The first big step whith Houdini is as you said to understand how to manipulate data, once you get that you can do anything. As Bournemouth graduate, I know that you have strong programming background so it will not be hard for you.

 

cheers,

Edited December 20, 2013 by cparliaros

[ch3]

nice... thanks a lot Christos.
I just watched the first lecture and it gave me some clues along with learning some of the features of the software. I will soon go through the other one as well.

 

georgios