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Everything posted by Farmfield

  1. How does Pyro FX works?

    There are a couple of breakdowns on this out there... But beyond these, you probably need to check actual research papers and if you go onto Amazon I'm sure there are math books on the subject that goes into this way deeper...
  2. FEM POPs two-way interaction

    I just use the outputs from the DOPs as collisions and/or use SOP solvers on the bullet solver to do stuff like attribute transfer of velocity, etc... And I won't share the above scene because it's an absolute PITA to work with but here's an example of "looping" DOPs and using SOP solvers on FLIP and bullet solvers - the scene file is linked in the description. I'll check it myself now because it was some time since I set that up and I don't really remember exactly what I did, but the foundation of it should be helpful, hopefully...
  3. FEM POPs two-way interaction

    When I've done stuff like this I've been looping DOPs in and out of eachother - with varying success - but there's no straightforward way to set this up, as far as I know... This is FEM trees, grains and bullet boulders set up like that - but it's a horrible setup to work with...
  4. Differential curve growth

    ...and a variant of the above... Scene files to both setups in the link in the description - and that's an open post on Patreon, just so that's clear.
  5. Differential curve growth

    Very clean scene file for distance based growth - scene file linked in the description...
  6. Differential curve growth

    Not sure what you mean, but just generally in regard to binding this kinda stuff to surfaces, doing extrusions or offsets, what I would do - and to make it work on any object - is remeshing the surfaces in the solver (slow as F, though, as it's a single threaded SOP) and then using the normal from the underlying surface (transfer it to the output from the solver, or inside the solver) to transform it off the surface, like using @P += normalize(@N) * some multiplier in a point wrangle...
  7. Differential curve growth

    Yeah, it's a lot of fun and you can do really cool stuff. Here's a setup I'll go through in my upcoming course, whenever I'll get that out - but yeah, it's in the works.
  8. Differential curve growth

    Man, it's really badly threaded, though, checking the performance monitor, the relax node isn't multithreaded so it'll just drag the whole thing to a crawl... I really would recommend setting this stuff up in POPs instead, using either the POP interact or the grain solver, it's just so much faster as they are multithreaded. And what expression? In the transform? That will fetch the information for which iteration you are currently on which is a detail attribute of the node I pointed to.
  9. Differential curve growth

    Oh, I forgot about this one, yeah, really simple, and gives a great behaviour. And this is how you'd use the foreach for the copying. diff_line_growth.FF.hiplc
  10. Differential curve growth

    Thanks, much appreciated. And just to be clear, I don't remember how Entagma set this up, I actually don't remember 90% of my own setups I posted on Vimeo, I have to go back and check all the time what the hell I did on one setup or another when people ask me how I thought, etc...
  11. Differential curve growth

    That looks really cool, Jonas, and loops are tricky sometimes, depends on what you're trying to do, but post the scene file with the loop and we can see how you thought - and I'd love a scene file either way, that thing looks really cool...
  12. Particles along surface

    Oh, ok, I think I understand the perceived problem, and then I'm with Matt, it's really nice to be able to set that up on a static object and then apply the animation on tip - of course depends on what you want to do....
  13. Particles along surface

    LOL; what? The minpos works just fine on an animated object... animated_minpos.hiplc
  14. sticky slime

    There are several tricks you can use for the sticking, like forcing it by raying the closest particles to it, but the stringiness I suspect you are looking for might be tricky to get without diving a bit deeper into the solver crap and play with stuff like gas elasticity - though you might be able to tweak it into existence balancing surface tension and viscosity, or at least that's what my instincts are telling me, hehe...

    Ran into this thread by accident now but yeah, the grain solver works great for doing packing - random points, increase pscale per frame until it collides with something and beyond that it's just making sure it doesn't birth new seed points inside current spheres. In this case I just locked the setup to a surface and used intersection analysis and the polypath to create the circles, but if you birth the points in a volume you have sphere packing and if you want to use more complex objects, you just set this up with the bullet solver.
  16. Differential curve growth

    Hmm, there's a slight weirdness going on in those clips so when I get time I'll put on a face mask, some rubber gloves, and investigate the mysteries of this organic compound.
  17. Animating along curves with UVs are one way, and the example files on cg-wiki are amazing, but I also love the sort shift point number thingie I've used in many setups, hehe - and I know it's stupid, but I just love it.
  18. Yeah, there's no need to go for POPs - and it all depends on what type of effect, how much control you want/need, etc... Here's a non simulated setup using find shortest path SOP.
  19. There is no deception used here, it's just quite simple, hehe... It's just a habit, rather than scattering a single point on a surface, I usually just use one off the surface, so a sort randomly and then delete everything except point 0. Here I sort by Y and then delete everything but the lowest one. So the bottom most point is there and I feed that into the POP. The convert line SOP converts every primitive to lines between it's connecting points. If I didn't delete the surface, the minpos function would ray the point to the surface, but here I just want the structure of the mesh for the particles to follow. And I didn't need the restlength, but I just didn't bother about unchecking it, doesn't have any influence at any point here accept eating a small amount of memory. And yes, the minpos function moves the point to the closest surface position of the target, in this case input two where I piped in the line structure of the half sphere. And finally the wrangle where I normalize velocity and multiply it by 0.1 to force a constant velocity of the particle - else its speed would be controlled by the noise function of the POP wind, with wouldn't be very fitting for particles representing some kind of information flow or alike. If you want different speeds for each particle, you could use something like multiplying the velocity with rand(@id).
  20. You could use a substructure for the possible routes for them to take, then you can have them behave half "free" and half controlled, so to speak. pop_ray_to_line.hiplc
  21. Resample curve by width/pscale

    Anyone know of a simple way to resample a curve by pscale/width attribute - or perhaps another way to space hulls in a sweep or alike by pscale/width so lower numbers will yield higher sampling..? And the idea is to get more square'ish quads for a setup like this, procedurally... resample.hiplc
  22. Resample curve by width/pscale

    Funny enough, this was again asked in the Houdini Artists Facebook group and I had completely forgot about asking this back in April... Either way, here's two other SOP based solutions to this problem, the second one a bit of a joke, of course - though I have no doubt that method can be useful for some things as well... v1: https://drive.google.com/open?id=1mjJd0vd9KUSFW79ksRc5fioeMxXnu6Bu v2: https://drive.google.com/open?id=1mjJd0vd9KUSFW79ksRc5fioeMxXnu6Bu
  23. Differential curve growth

    Just wanted to post this as an example of using this technique as foundation for something else. Scene file in the Vimeo description.
  24. N-body via SOP solver with OpenCL

    Upped both scatters to 100k points and it still sim'ed 300 frames in about 2 minutes - just crazy. Very cool.
  25. Bullet: Activate on Collisions or Start Sleeping

    I have no clue what this was about, though - that was 13 months ago, I gotta download and check the file.