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YaserH

Rigid Body Simulation Question - Switching from animated geometry to simulated

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Hi all,

I am trying some simple tests in dops using the bullet solver. I have hit a few stumbling blocks and would appreciate any input from you friendly people :)

What I'm trying to do: I am trying to get a scene showing a pillar being picked up by a crane (like the ones in fairgrounds where you can use it to grab soft toys), the base of the pillar stays where it is and the rest of it gets picked up by the crane.
As the pillar is picked up, the lower part of whats left is crumbling away as the whole thing moves.

The setup: Because this will eventually be put into a game engine, I have to keep the number of fractured pieces down, so I split the pillar (Top, Bottom), and then I split the Top even further to isolate the "destructible" area. I fracture this area and animate both objects to be moving with the crane (transform sop within the SOP level)
I then bring these objects into a dop network as RBD packedobjects but I can't seem to bring in the animation that is attributed to them. I change the "Initial Object Type" to all the the available selections int he dropdown, including Create animated static objects" but this doesn't seem to do anything.

I do know you can do this on an RBD fractured object using the Use Deforming Geometry checkbox, but I'd prefer to work with packed geometry to reduce simulation times. 

 

Ideally, I would want the destructible area to just be parented to the Top of the pillar and then I can make it crumble by breaking the constraints. But I can't seem to do that either. 

In 3DS Max, in PhysX, there is an option to tag objects as "Kinetic" and then choose which frame to make them "Dynamic". That's a very rigid way of working and I'm certain there is a much more flexible way to do it in Houdini but I am still a beginner, especially when it comes to rigid body simulations.

 

So to summarise, the questions I am left with are:
How can you bring in animation on an RBD packed object?
What would be the best way to achieve what I am trying to do?

 

Thanks

Edited by YaserH

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Ok, I've just found the issue :) 

I have it working now. I went wrong by added a facet to pre-compute the normals of the mesh, but I had, for some strange reason, checked Unique Points on. This was preventing the pieces from being chunks and rather instead be individual primitives.

I changed the Initial Object Type to Create Deforming Active Objects on the RBD Packed Object node and it all works as expected.

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