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Rbd Fractal Object


tleisher

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When I try to make an object into RBD object, then make it into a Fractal object (So that when I drop it onto something, it shatters) but it gives me an error when I try to do that, says that the object is already simulated.. which makes sense. So instead I just make it into an RBD fractal object, which works fine but then why I play my animation it doesnt have any gravity.. it just sits there. Even with a gravity node attached to it, it just sits there.

The documentation just says to click the fractal button, then click the object and hit enter. I did that, but it doesnt work, what am I doing wrong here? Is the fractal object not what I want to do in this situation?

Are there any good tutorials, DVDs, guides, etc for Houdini 9 Rigid body dynamics and making things shatter?

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yeah this is busted...

I'll test again at work tomorrow...

you should load the Example Files in the Documentation...

on the Help Page:

bottom right

Reference

Example Files

Dynamics Node Examples...there are lots in there...

the one you want to look at is called "BreakingRock"

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I believe the problem you are having is that the object you are trying to turn into a Fractured object does not have the necessary groups setup. The Fractured and Glue objects are different than the standard RBD object in that they rely on primitive groups in order to create individual objects in the simulation. If you took a standard box and tried to create a Fractured or Glue object, nothing would happen. However, if you grouped all the primitives and then ran the tool it would work correctly.

In the attached file a cube has been copied to a grid and then run through Connectivity and Partition SOPs to create a group for each cube. When fed into DOPs now, by looking at the Details view you can see that there are 100 Box objects in the simulation. If you remove the object from simulation, bypass the Partition SOP then run the tool again and look at the Detail view you will see that it has not created any DOP objects because the source geometry has no primitive group information.

fracturedexample.hip

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Alright cool, I have a new problem now though. I'm trying to make a wrecking ball come down and smash through a peice of glass... shattering it into peices. I'm trying to get the glass to divide up so I can properly break it apart.. but nothing I do seems to increase the amount of triangles that make up the mesh.. I've tried using a Grid and a Cube.

I've been using TriDivide and PolyReduce (as per this tutorial) but none of them seem to do anything. I've also tried Divide, which didn't do much either.

Any ideas how I can increase the amount of polygons/triangles on a grid or cube?

Edit: I got it to work, setting the grid to triangle instead of polygons helped I think.

Edited by tleisher
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