nicoladanese Posted February 23, 2018 Share Posted February 23, 2018 Hey all! I'm shattering an object with voronoi and obviously the result is a bunch of pieces with straight segments, but what I want is pieces with curve profiles, like the image attached. does anybody have any idea on how to achieve that kind of look? cheers! Quote Link to comment Share on other sites More sharing options...
kiryha Posted February 23, 2018 Share Posted February 23, 2018 You can shatter your objects with a boolean using custom handmade geometry, it will give 100% control over shatter shape. Quote Link to comment Share on other sites More sharing options...
nicoladanese Posted February 23, 2018 Author Share Posted February 23, 2018 hmmm...nice idea, maybe I can create some macro pieces by hand and let the voronoi shatter do the rest Quote Link to comment Share on other sites More sharing options...
kiryha Posted February 23, 2018 Share Posted February 23, 2018 (edited) Watch from 36:40, you can handle all cracks with boolean, completely art directed control. Edited February 23, 2018 by kiryha Quote Link to comment Share on other sites More sharing options...
ParticleSkull Posted February 23, 2018 Share Posted February 23, 2018 Hey Nicola, like Kiryha said, go by boolean. You will have the perfect control over those shapes. Voronoi fracture is an old technique, imo. It's still good in some situations but not at all for other ones. There's this awesome tutorials by steven knipping: 1 Quote Link to comment Share on other sites More sharing options...
toadstorm Posted February 23, 2018 Share Posted February 23, 2018 Keep in mind that if you plan on simulating these pieces via Bullet / Packed RBD, you will probably still have to voronoi shatter each individual booleaned piece and then glue the pieces together in order to create reasonably accurate convex hulls. Quote Link to comment Share on other sites More sharing options...
coltonmil Posted February 23, 2018 Share Posted February 23, 2018 (edited) 22 minutes ago, toadstorm said: Keep in mind that if you plan on simulating these pieces via Bullet / Packed RBD, you will probably still have to voronoi shatter each individual booleaned piece and then glue the pieces together in order to create reasonably accurate convex hulls. Is it significantly faster to sim with a larger number of simple convex hulls than one complex concave? Edited February 23, 2018 by coltonmil Quote Link to comment Share on other sites More sharing options...
toadstorm Posted February 23, 2018 Share Posted February 23, 2018 I don't know about faster, but it's definitely much more stable. Concave shouldn't even be an option IMO, it basically never works. Bullet really hates anything that isn't a convex hull. 1 Quote Link to comment Share on other sites More sharing options...
ParticleSkull Posted February 23, 2018 Share Posted February 23, 2018 (edited) I always simulate with convex collision shapes and most of the time you can't see the diference at the final sim. I think it totally worth it Edited February 23, 2018 by ParticleSkull Quote Link to comment Share on other sites More sharing options...
toadstorm Posted February 23, 2018 Share Posted February 23, 2018 I'm assuming you meant concave shapes? Either way, from Houdini's Bullet Solver docs: Quote Collision of concave shapes is known to have some problems, and is not fully supported. It's possible to get satisfactory results with concave collision objects, but in practice you're better off with convex decomposition. Quote Link to comment Share on other sites More sharing options...
ParticleSkull Posted February 23, 2018 Share Posted February 23, 2018 Nope, I mean convex shapes. I know it looks weird and the simulation shouldn't look right but, if you have a lot of pieces it's impossible to notice it has a "wrong" collision shape. Concave is too expensive on calculation and do cause a lot of problems. In this situation, with just a few pieces, you could break each piece into smaller ones to have a better collision shape. You know what I mean? Then you can glue the smaller pieces together to form the big piece with a better (but not perfect) shape. Quote Link to comment Share on other sites More sharing options...
toadstorm Posted February 23, 2018 Share Posted February 23, 2018 Sorry, misread you, I thought you were saying concave made no difference in finals! Sounds like we're saying the same thing then. Quote Link to comment Share on other sites More sharing options...
ParticleSkull Posted February 23, 2018 Share Posted February 23, 2018 Yeap haha I did an example. Have a look at the file, it works pretty fine with the convex collision shape RBD Boolean Fracture.hiplc 1 Quote Link to comment Share on other sites More sharing options...
vtrvtr Posted February 23, 2018 Share Posted February 23, 2018 You can use the vdb to spheres technique to get around the concave bullet problem. It works quite well. https://i.imgur.com/HBIF1l1.gifv 2 Quote Link to comment Share on other sites More sharing options...
ParticleSkull Posted February 23, 2018 Share Posted February 23, 2018 hey @toadstorm, your article about texturing flowing liquids saved my life once! Thx by that 1 Quote Link to comment Share on other sites More sharing options...
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