Fracture Otl Groups

[ihab]

Hi Guys,

I'm a dops noob and i'm trying to make a dops simulation where objects are shattered upon impact with one another. I downloaded the Fracture Sop from the exchange website and used it to pre-fracture my geometry. The problem is that the Fracture sop always creates groups named (obj0, obj1 ...etc) for every object it fractures. And there's multiple fractured objects in the simulation . I bring the fractured objects into the simulation as rbd fracured object. Later on when i try to extract the geometry into sops using an object merge sop i use the syntax specified in the houdini help (/obj/dopnet1:rbdobject1/Geometry) i replace the rbdobject1 with rbdfracturedobject1 as in my case but it doesn't work.

if i try (/obj/dopnet1/obj*) it brings all the objects in the simulation.

Is there anyway to extract each fractured object back to sops?

thanks in advance.

[MIguel P]

You have to write:

/obj/dopnet1:obj*/Geometry

Edited April 27, 2007 by MIguel P

[rdg]

[quote name='MIguel P

[ihab]

thanks for the reply guys,

but you see the problem is if i use obj* i get all the fractured pieces of all objects. I'll give you an example.

say i have a ball i ran into the fracture sop and it has 20 peices (obj 0 - 19). then i have a wall i ran into the fracture sop and it has 50 pieces (obj0-49).

inside the dops simulation there's 2 objects named obj0 , obj1 ...obj19. then there's obj20-49 that belongs to the wall.

so if i use obj* i end up getting all the pieces of both the ball and the wall. The problem is that the fracture sop creates the groups by itself and i have no way of renaming them.

cheers

[MIguel P]

You can create an attribute with different values for each object (ball and wall) and then in SOPs use the Delete SOP with delete by expression.

[johner]

thanks for the reply guys,

but you see the problem is if i use obj* i get all the fractured pieces of all objects. I'll give you an example.

say i have a ball i ran into the fracture sop and it has 20 peices (obj 0 - 19). then i have a wall i ran into the fracture sop and it has 50 pieces (obj0-49).

inside the dops simulation there's 2 objects named obj0 , obj1 ...obj19. then there's obj20-49 that belongs to the wall.

so if i use obj* i end up getting all the pieces of both the ball and the wall. The problem is that the fracture sop creates the groups by itself and i have no way of renaming them.

cheers

You can toggle off the "Build Groups" option on the Fracture SOP, then just append a Partition SOP to build the groups yourself, named however you like. So in your case, maybe "ball_$CLASS" and "wall_$CLASS" for the Rule parameter in the respective Partition SOPs.

[ihab]

@MIguel: I think this will work but it will be very intensive in cases of large amount of objects.

thanks Johner. That's exactly what i've been looking for.

rdg did a nice tweak to the otl where you specify a prefix for the groups created by the fracture.

thank you all for the help