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anupamd

non voronoi more realistic fracturing.

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(kudos to Matt Radford)

First check this out, 3DS max + thinking particles / volumebreaker. This is seriously good guys, we should be able to do this with houdini... the physics is fairly straight forward with gluenets and bullet, but the issue is the fracturing and getting that to look natural.

Has anyone looked in to fracturing geometry without using voronoi? The fragments that voronoi produces often look un-natural and sort of rock-like. Im interested in coming up with a solution if none exists, and I thought I'd start a thread about it.

So one solution is to go through a for-each and chop up geo with cutting planes, this has been attempted before by others on odforce.. but it seems to be that the cookie sop produces bad geometry and is UN-reliable. I believe there was talk of "fixing" the cookie sop but clearly sidefx hasnt done anything yet... so there is there bottleneck .

Is there a better cookie sop out there somewhere?

Edited by anupamd

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Actually volume breaker in TP uses voronoi to fracture. You can use "cells"(particle clouds) to activate and place your fracture, scale in xy and z and joint pieces together but its still just a voronoi pattern. (maybe has some dispacement or a nosie mod post sim),

The biggest difference for me between houdini and TP rbd sim's is the speed. TP is much faster but I have used TP alot more than I have houdini so it could just be me .

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He talked about this in an interview http://www.3dworldmag.com/2012/09/27/meet-the-3d-artist-blur-studios-matt-radford/

1. If your procedurally destroying something with voronoi fracturing (in Thinking Particles or Houdini). An easy way of avoiding the ugly voronoi look is to break it once into 20 pieces or so, then fracture each of those pieces heavily, but only activate 30-60% (I usually go from -Center). This will get you a lot of really interesting looking bigger chunks and lots of little small debree – this, however, is not the most efficient method.

im not sure how you'd only active a percentage of them but keep them moving along with the others though?

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If you change the metric with which voronoi measures distances you can achieve different kind of looks. I have never seriously looked into it but it would be one of the first things I'd try to change.

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If you change the metric with which voronoi measures distances you can achieve different kind of looks. I have never seriously looked into it but it would be one of the first things I'd try to change.

How do you change the measuring system that the voronoi sop uses?

Could you explain this method a little bit more in depth?

cheers,

Juri

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Well i think what Macha means is deform the space that the fracturing takes place. See attached HIP. So yea, you can do this now by just deforming the object, fracturing, then deforming it back. Here is a quick example of that I came up with. I have to say it looks way better than I expected.. and actually looks better than the odd looking voronoi patterns. Im playing with other techniques too and I'll post sample hips here if I come up with anything interesting.

.. now if I could only figure out how glue networks work.. argggh!

fracture_deform.hip

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Revisiting this post. One year later, we are now on houdini 13. Cookie sop is still broken........

 

Seriously.. what exactly is the problem here. Why cant SideFX just fix the cookie sop? That way we can do some really nice looking fracturing using custom patterns for cutouts..etc. (like Volumebreaker). Is everyone just happy with the way clustered voronoi fracturing looks? :/ Or is everyone using 3ds Max now :)

 

Ok, in desperation I'll ask the obvious next question. Assuming Im just going to write my own cookie sop, is anyone aware of good opensource computational geometry library that does good reliable booleans. I found this, but it seems to be only a 2d clipper. http://www.angusj.com/delphi/clipper.php

 

I mean, We sent robots... to MARS! 

Perhaps we can figure this out?

 

-Anupam

 

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He talked about this in an interview http://www.3dworldmag.com/2012/09/27/meet-the-3d-artist-blur-studios-matt-radford/

1. If your procedurally destroying something with voronoi fracturing (in Thinking Particles or Houdini). An easy way of avoiding the ugly voronoi look is to break it once into 20 pieces or so, then fracture each of those pieces heavily, but only activate 30-60% (I usually go from -Center). This will get you a lot of really interesting looking bigger chunks and lots of little small debree – this, however, is not the most efficient method.

im not sure how you'd only active a percentage of them but keep them moving along with the others though?

I agree with this comment, it is important to have size variety among the pieces, and the rest is just, displacement on the inner faces together with points sharing outer faces. In fact I am watching my failed attempt at the moment where two of my caches are doing just what I want and one is crumpling equally, they both use similar patterns for voronoi, but glue constrain parameters are playing a great role for the right look and feel.

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