Destruction - how to improve the dust and debris simulation?

[Hudson]

Hello there,

I was not sure if I should post this in WIP or here. please let me know if I posted it in the wrong place

I am still a noobie and this is my first simulation I have ever done. It is a fissure cracking its way to a building and part of the building collapses. The destruction is done with bullet within houdini 12.1.

I know the main simulation of the pieces isn't the best although I am pretty satisfied with the result of it and would rather spend more time improving my dust sim and specially the debrises. But if you have any idea how I could improve the main pieces simulation I am glad to listnen

The flickering on the ground pieces could it be because they are moving? I am expanding a geometry under the crack to lift up the fisure a bit. Could it lead to the "flickering"?

Debris: as you can see in the debris sim my debrises are behaving a bit weird. They are boxes copied to the faces of the fractured pieces. Their creation is based on the velocity threshold from the fractured pieces. I other words the same solution presented in the bullet masterclass.

Most people say that how you create debris depends on the shot. Someone has already recommended me to use particles and just let them collide with the ground of the building instead of all the pieces. what would you recommend?

Dust: I am not sure about the thickness(density) of the dust itself, does this example feels like there is too much dust?

The dust is created with a bit of delay even tho it follows the fractured pieces. Any idea how I could solve this problem?

Any other inputs are appreciated.

I will attatch the hip-file and two video:s one for the sim with dust and the other with the debrises.

The simulations are pretty heavy so you know.

regards,

Hudson

Edited April 17, 2013 by Hudson

[traiano]

Hi, thats a great start.

I recommend to create debris with particles and for that, you have to fracture the geometry with groups of pieces so that you can get the inside pieces and emit particles from there.

If you are going to fracture the rigid bodies again try to get more variance in pieces size and smaller than the ones you have now.

As for Dust, you can use a time warp in order to tell when dust start so you syncronize better with your geometry animation.

[Hudson]

Hi Martin,

Thank you for your tips!. I will definitly check out the time warp to sync the dust with the geometries.

First of all, to get more variance in the RBD pieces would you tweak the scattering points for the voronoi fracture pieces or tweak something else?

When you mention that I should fracture my pieces with groups instead of entire pieces. Do you mean that I should keep the glue net for a few pieces so they can create a secondary fracture when they hit the ground? Or did I missunderstood you? I will do a bit of research my own to see if I find something.

The thing is that I wanted to do is myself from the very beginning. So to say cluster smaller pieces with the help of the glue net by changing the glue strength around a few pieces. The problem I faced was the fact that I used scatter on a geometry to change the glue strength for my network and the offset of the scatter reached pretty far. So I couldnt change the glue strength around a few pieces to create a group of pieces glued together. instead I had to add the same strength to all the pieces. The video attatch show you what I mean.

Glue network change strength value demonstration: https://vimeo.com/62053422

Also, I hope your computing issues were solved. For this dust sim the bgeo-files reached only 10mb in size and it took my machine around 7h to simulate all 240 frames, I am currently on a laptop with i7-3610QM and graphics GTX 675M and 16gb ram. the division size was 0.02 and I only simulated vel, den and temperature. the scale of the scene was based on a real house.

/Hudson