So, i've a problem with importing a obj file and the use it in a dynamic sim.

my obj file contains some non connected geometry, i want this different pieces to behave as individual objects in my simulation.

i use the RBD Fractured object in my dop, then in my geo node, i first add a connectivity node, declare a variable, the i ad a partion node with the rule set to the connectivity nodes name.

but still, my geo behaves like a snigel obejct.

please help!

Maybe try an RBD glue object ?

R

i tried that as well, and the same result.
here just a test object i use now when i'm figure out the problem.

i can not use this sphere in a simple RBD Fracture sim.
here's the file obj file remove .hipnc and add (.obj) to it.

thanks for any help!

What non-connected geometry? When I import the .obj, I see only a sphere that has all primitives connected.

i reduced my scene to find out the problem, and the problem seems to be obj file. i can't even get that simple ball to act as a RBD Fractured objekt when i copy it to a plane.

Use a Facet sop right after the Sphere sop and Unique the points.
You will likely have to adjust the Glue Strength and/or the Glue Impulse.

sorry, but i still get the same result with the Facet sop….

klasse
i reduced my scene to find out the problem, and the problem seems to be obj file. i can't even get that simple ball to act as a RBD Fractured objekt when i copy it to a plane.

But that sphere is one connected piece of geometry. You need to pre-fracture it.

yes i know, but the problem is i can't the sphere to act in my RBD Fractured simulation.

do this:
use the copy node to copy the sphere to a grid. then turn that into a RBD Fractured object. create a ground plane. the sphere should now act as single non connected spheres, but they don't they act as one big object instead.

although i solved this by exporting my object as fbx instead of .obj.
but i would really like to know why the obj file isn't working.

thanks.

The problem with your copying the sphere is that in order for the Fractured/Glue objects to work, each different object must be in it's own group and that group string should be set in the mask on the dop object. Houdini can do this automatically for you when the tool is invoked if your input geo doesn't have an groups; if it does it leaves it up to you to have it setup. In your case, all the spheres belong to the 2 groups your geometry has on it already.

To make this work do the following:

After you have copied your sphere to the grid, append a Group sop. Go to the Edit tab and in the delete tab, place a * in the group field. This will destroy your two default groups. Now you can run the RBD Fractured/Glue Object tool and it will behave as you expect.

beautiful
thanks so much!