RBD Point Object Problem!!!!!!

[Anton]

Hi! I created a cloud of points, and trying to create simulated object on each point. I have a sequence of 30 individual geo objects loaded from disk: geo_0001.bgeo, geo_0002.bgeo, geo_0003.bgeo and etc in file sop. How can i randomly load all this objects from different frames into RBD Point Object. As i understand i have to create an attribute for source points in SOPs and use this attribute in RBD Point Objects node. I little bit confused how to do it?

Edited November 20, 2012 by Anton

[jhiggins]

i would take your points

1) copy stamp the geometry from the file sop

2) throw down an assemble node after the copy which will create a name attribute for you that varies per geometry.

3) use a rbdfractureobject instead of rbdpointobject and point it to your copy stamped geo.

good luck!

[Anton]

OK! Thx jeffrey.higgins i solved it with blend solver and rbdfractureobject to control all pieces, but RBD Point Objects seems to me would be better.

[jhiggins]

yeah... i honestly don't think its too different, you could always use the different bullet types ( box, capsule to speed up the simulation), but if you wanted to used the rbdpointobject still... you could probably attached a scale or pscale attribute to your points that would ideally match the shape of the geometry and then pass those points into the the rbdpoint object for the simulation instead of the geometry but then after the dopimport on your points you would do the same copy sop to stamp on the simmed points to get the geometry back onto it.

out of curiosity what is the blend solver being used for?

[rafaelfs]

As far as I know you can't really specify geometry from disk, at least not directly.

What you can do is load this geometry into houdini and then create an "instance" attribute pointing to the geometry containers of each geo.

Cheers

RBD_point_example.hip

[jhiggins]

thats a cool example, but it has the problem that you have to have all of your instances loaded first and live separated at the object level and often enough they live on disk and you have varying numbers of them.

It would be cool if this workflow worked with the instancefile attribute which allows the Point Instance Procedural to delay load them at render time in mantra. Having the same approach for simulation would give a lot of flexibility.

[rafaelfs]

thats a cool example, but it has the problem that you have to have all of your instances loaded first and live separated at the object level and often enough they live on disk and you have varying numbers of them.

It would be cool if this workflow worked with the instancefile attribute which allows the Point Instance Procedural to delay load them at render time in mantra. Having the same approach for simulation would give a lot of flexibility.

Well, if you think about it, they would have to be loaded anyway before the simulation would run. Unless you're running the sim from hbatch, or your sim geo is expensive to cook, I don't see a real advantage to running a sim with geo loaded directly from disk (unless, of course, the geo only exists on disk). This case is a completely different scenario than delayed-load rendering which cuts time and memory consumption by skipping geometry description in the IFD generation.

Cheers

Edited November 26, 2012 by rafaelfs

[jhiggins]

yup, you have to load the geo either way, this is just a different way, one which if you do so would make it easier to render with that procedural. I didn't intend to suggest that the simulation would be delay load, sorry! I like being able to load geo from disk b/c geometry tends to already live there to begin with and then you can vary the number of geometry you use in your simulation much more easily.

its how i would do it, but to there are many ways to do anything, so to each their own!

cheers,

j.

[bloomendale]

here is simple example:

i changed point rbd object dop a bit so that it loads different geo based on the point attribute for every point. Colored in red all modified nodes.

Just save frags first (use "frags" geo node), then alter the path to those files in point rbd object (i used the sop path parameter for it).

3ak_random_point_RBD_shape.hipnc

Edited November 27, 2012 by bloomendale