Ground Explosion

[victo160]

Hi, 

I'm trying to create a scene where a 'missile' hits the ground and causes an explosion. I wanted to the ground to explode too, chunks of rock fly up as well as the pyro explosion. I created the ground from a simple geo and applied the fracture and created the pieces I like. My issue is, how do i make this explode in the dop-net? I bring it in and have a tube object coming from below it to create the explosion fracture, but the pieces fall off screen since they are effected by gravity. When i add a ground collision object the TUBE object doesn't go though it and doesn't fracture the piece. 

 

My question is, how would I make it so the fractured object gets "blown up" with the pieces landing on the ground and so my colliding object can hit the fractured object without getting blocked by the ground. 

 

Thanks a lot for any help!!  

 

Any examples or knowledge of pre-exisiting examples/ tutorials would be awesome!

[Juraj]

Hi,

have you tried postioning your fractured ground geometry on top of ground plane? Make your tube a static object and that way it will influence your simulated geometry and will be able to pass through ground plane.

If you want to have greater control above motion of exploded chunks you can use nice technique described in this video. Then you can combine collision with your tube and with sculpted velocities. 

 

 

Juraj

[Farmfield]

Oh, don't link to that guy's crappy videos, he doesn't know sh!t.

 

To be honest, I think creating point clouds with velocities is probably the most useful knowledge you can have in regard to setting up dynamic in Houdini, be it fluids or RBD, FEM, grains, everything is 100% controllable through such setups. The next most useful knowledge is IMO using VDB's and volume sampling to control dynamics.

 

Because it's all about control, getting stuff to behave exactly how you want it to.

[magneto]

Oh, don't link to that guy's crappy videos, he doesn't know sh!t.

 

To be honest, I think creating point clouds with velocities is probably the most useful knowledge you can have in regard to setting up dynamic in Houdini, be it fluids or RBD, FEM, grains, everything is 100% controllable through such setups. The next most useful knowledge is IMO using VDB's and volume sampling to control dynamics.

 

Because it's all about control, getting stuff to behave exactly how you want it to.

 

What do you mean creating point clouds with velocities?  You mean using Fluid Source SOP?

[Farmfield]

Check the scene file I link to in the description for that video. I create a point cloud from a mesh converting it to a volume and scattering points in it, then I create a null to represent the explosion center and then I use a VOP to calculate the vector from the explosion center null to each point in the point cloud and store that in the velocity attribute for each point. Now I can feed those values into a simulation, doesn't really matter if it's FLIP, RBD, Pyro, to sculpt the input - like in the video.

 

Here I use a similar technique to create a point cloud from an animated spline, then calculate the cross product from the spline to the point and the up vector (adding some noise in the VOP) to create a "vortex field", then I birth particles on a plane and feed them the velocity values...