michaelb-01 15 Posted November 18, 2015 I'm sure lots of people have seen a recent video by Kouhei Nakama on vimeo - I'd really like to see if I can recreate this in Houdini. It looks like diffusion limited aggregation but also looks slightly different and i'm wondering if anyone has any insight on how to achieve this effect? The part i'm mostly unclear about is the leading edge of the diffusion - there seems to be an edge perpendicular to the direction of diffusion, which I don't think is common in DLA? This also looks like displacement so could this be achieved in COPs somehow and applied as a displacement map? Share this post Link to post Share on other sites
petz 433 Posted November 18, 2015 its not dla but reaction diffusion (http://www.karlsims.com/rd.html) the algorithm is quite simple and easy to implement in houdini. do a search here and on the sidefx forum. i believe this topic came up several times over the years, probably with example files. 1 Share this post Link to post Share on other sites
michaelb-01 15 Posted November 18, 2015 Ah I see, thanks! This should be possible in COPs right? And then you could apply it as a displacement map? Share this post Link to post Share on other sites
petz 433 Posted November 18, 2015 Ah I see, thanks! This should be possible in COPs right? And then you could apply it as a displacement map? that would be one possibilty, yes. but depending on the geometry it might be easier to apply the algorithm directly on points or prims without using displacement maps since you won´t need uvs in this case. petz 1 Share this post Link to post Share on other sites
michaelb-01 15 Posted November 18, 2015 I have a basic version working in SOPs now but I would imagine the geometry could get very dense and slow to work with. How could you do it in COPs? Is there a solver in COPs? Share this post Link to post Share on other sites
petz 433 Posted November 18, 2015 I have a basic version working in SOPs now but I would imagine the geometry could get very dense and slow to work with. How could you do it in COPs? Is there a solver in COPs? well, i don´t know how big your geometry is but using vex it shouldn´t be a problem to do the calculations on a fairly dense mesh. i´m not sure if cops would be faster tbh. no, unfortunately there is no cop-solver. at least not that i know of. you either have to save and load the images or use chops together with cops. petz Share this post Link to post Share on other sites
michaelb-01 15 Posted November 18, 2015 ok, thanks for your help. Share this post Link to post Share on other sites
animatrix 210 Posted November 18, 2015 I made a VEX implementation of this before. The speed is consistent across different contexts, i.e. COPs vs a slice of a volume with the same resolution. Some of the VOPs shown in the video: http://www.orbolt.com/asset/animatrix::reactionDiffusion::1.00http://www.orbolt.com/asset/animatrix::pointCloudLaplacian::1.00 1 Share this post Link to post Share on other sites
fathom 79 Posted November 18, 2015 I have a basic version working in SOPs now but I would imagine the geometry could get very dense and slow to work with. How could you do it in COPs? Is there a solver in COPs? use a pointcloud instead of trying to have a crazy high rez mesh. then use that pointcloud at rendertime to displace/color your surface. Share this post Link to post Share on other sites
