goldleaf Posted February 12, 2015 Share Posted February 12, 2015 I've been getting back into FLIP, and trying to replicate this test done in Naiad a while ago: https://vimeo.com/25020677Using some POP nodes, I know I'm getting attributes changed on the points properly, but I can't figure out why the solver isn't pulling the higher density particles down under the lower density ones. I even played with @mass, hoping that'd do it, but it doesn't. The POP nodes are affecting the points just fine; when I crank up viscosity/velocity/color, those are set properly. The red points should be rising up, and the teal/blue ones should be sinking since they're heavier: Does anyone have some insight(s) as to why the density isn't making points rise/fall?Thanks! dense_flip_separation.hipnc Quote Link to comment Share on other sites More sharing options...
Skybar Posted February 12, 2015 Share Posted February 12, 2015 The density attribute on all points is actually 0. You never actually set it's value anywhere, all you do is multiplying a few of them by 0.0001. Multiply that to zero and you get zero, while the other points will have zero as well. Quote Link to comment Share on other sites More sharing options...
goldleaf Posted February 12, 2015 Author Share Posted February 12, 2015 (edited) Well shoot, I thought it set the Density to 1000 (set on the Dop Object) if there was no incoming density, but I guess I was wrong! Thanks Skybar! I'll upload a hip file when I get what I'm looking for, but here is an image of it all working. I also had to make the differences between the two densities a lot larger (the light weight foam is 1/1000th of the water). Edited February 13, 2015 by goldleaf Quote Link to comment Share on other sites More sharing options...
sergio Posted February 15, 2015 Share Posted February 15, 2015 Hi Chris, After seeing your video on vimeo i decided to take a go with it. But your foam is clustering way more strongly? can you tell me, what is in my file is different then yours? thanks. Foam_Generation.hipnc Quote Link to comment Share on other sites More sharing options...
goldleaf Posted February 15, 2015 Author Share Posted February 15, 2015 Hi Sergio, I'm not 100% sure, but I think it's because you're only setting density, not viscosity. I added that to your hip file, and I'm seeing foamy-ness. Also, something I noticed, is it's easy to convert too many into foam, and that can make the foam form a huge ball that rises to the top and floats. That's a function of how you're creating your foam grp so I made a few modifications to your file, so that not so many points are "foam-ified" at the same time. Also, over on the SideFX forum, johner graciously provided some great help, check out his tips/hip files: https://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&p=171883 (that's why I added the gas stick on collision, and how I was able to solve some other issues). I also attached my hip file for the vimeo video to that thread as well. Hopefully those help guide you in the right direction! Foam_Generation_modified.hipnc 1 Quote Link to comment Share on other sites More sharing options...
sergio Posted February 15, 2015 Share Posted February 15, 2015 Chris thank you very much for the detailed answer. I didn't see your post on the side effects forum before and yes johner's explanations are great. Quote Link to comment Share on other sites More sharing options...
ouroboros Posted December 28, 2017 Share Posted December 28, 2017 how does the lower density particles surface to the top though? Does it happen automatically? If not, how do I set up a threshold telling the solver when to surface and when to sink? Thank you guys very much, this has been a very interesting topic Quote Link to comment Share on other sites More sharing options...
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