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Found 114 results

  1. Pop Collision Ignore + Grain Solver

    hey guys, is there a way to make the Pop Collision Ignore node work with the grain solver? I really need to avoid the collision of one granular solid object, it works fine with normal particles but not with the grain solver. grains_avoid.collision_1.01.hiplc
  2. particle split loop

    hello, I have been try to make some effect by particles. I was trying to use pop network to make something like particles split. but if I use POP replicate. it only split once. How can I make particles split loop? just like 1 to 2 and 2 to 4 after that. I can't find a way to make it happened. thx
  3. Agent interacting with Pop Grains

    Hello everyone, First time poster. Coming from a C4d / Realflow background. I have been able to accomplish what I am trying to do with regular objects as a sphere or a cube lets say. I downloaded a zombie crawl from https://www.mixamo.com/#/?page=1&query=zombie . I imported the fbx into an agent and added an unpack node under the agent as I read this was the only way to be able to get it to react with RBD / Fluids etc. My scene consists of a cube with a transform on it to make it a rectangle which I applied a wet sand preset. The rectangle is above the imported fbx zombie. I have a ground plane. I tried making the zombie a RBD and I also tried making it a deforming object. The goal is to sim to grains with the zombie in place (I removed the $T animation channel). Once the grains seemed to be settled and looking like a nice pile of dirt, I spit out an initial_state.sim file. I added the to my dop network. I then selected the zombie and clicked on Awaken by Geometry. I also turned on Enable auto sleep and Start asleep on the pop solver. I am having several issues. I would like once I have my initial state, for all the particles to be frozen or "asleep" unless the zombie interacts with them. Also I was to be able to control the velocity of how his movements affect the particles collisions... and those particles would in turn AWAKEN more particles etc. I can not get any of those to work. I searched every post on the forum with grains. I learned a few things from Rohan Dalvi's tuts. So I am kinda stuck and hoping someone could help me out. I have attached the latest iteration of where I am currently (stuck). Let me know if you have any questions on my end. I just recently bought indie and redshift and loving it so far. Still wrapping my head around attribute wranglers and vex, but one day at a time. Thanks guys! William grains_zombie_crawl_006.zip
  4. Hi I am trying to do this old POP tutorial, there is a section where he takes the red color value and modulates it with a spline ramp. (around the 4 mins mark) For some reason I cant recreate this at all. He is using a VOP sop and I am recreating it in an attribute vop , i think that should work fine . when i connect my ramp it just removes all the color. Thanks https://vimeo.com/95644892
  5. velocity field question

    hello guys, I tried to get velocity field in to POP and use advect by volume. but particles stop moving when they reaching some position. I can't find the reason of it and how to fix it. Does anyone can help that for me please? vortex_field_problem.hipnc
  6. Noise in particles

    I sim a particle system, I want to put some nois after sim but Cd color is not baked at the particles, how can I baked it ? does Anybudy have clue ?
  7. POP Wrangle Group

    Hello, I want a second age ("myage") for particles, when they are in the group "active". Very simple? But it don't work
  8. Geometry particles PopSpin

    Hi all! I hope this isn't a dumb question, but I'm stuck getting my particle shapes to spin. I might be approaching this wrong... I've fractured and packed an object. I bring the pieces into the POP network, instancing each piece with source emission type set to All Geometry - each particle is a piece from the fractured geo. Now I just want these pieces to spin. I do get the w attribute set, but, the pieces themselves are just translating with the particles, not rotating. A simple scene with the setup is attached. Can anyone point me in the right direction here, and perhaps explain why this approach doesn't seem to be working? Thanks! popSpin.hip
  9. Hey! I'm scattering some points and then use them as first input in a popnet to sim it. in the pop source I'd like to just emit a point for every source point, so basically I'm emitting for 1 frame with the same number of points, to get the same points in the sim. is there a way to tell the pop source to emit the exact number of points you have as input (at the mo I'm just manually putting the number...) ? cheers!
  10. Hello! I'm using grains to fake cloth and I'm having this weird issue where I'm using a popwrangle to update my targetP (because the constraint points are animated), and it seems to be dragging the target points towards the origin? I've compared my set up to a couple example files and can't quite figure out what's gone wrong. Any help would be appreciated! Example file attached targetPointIssue.hiplc
  11. Hello everyone! I'm just wondering if someone knows how to create that a Particles meets and other particle stick togheter, and if is possible to made that. If there is a particle floating around and get close to an other particle floating around can they stick togheter. or any way that I can aproach that?
  12. Particles

    Hello everyone! I'm just wondering if someone knows how to create that a Particles meets and other particle stick togheter, and if is possible to made that. If there is a particle floating around and get close to an other particle floating around can they stick togheter. or any way that I can aproach that?

    Hello !! I have a quick question I little more advance, how can I make a particle collide with a geo and make it sticky on the surface and slide down? I try to use the particle behavior but maybe I, doing sth wrong. some have a solution, I will appreciated.
  14. Randomize Const. Activation

    Hello! I want to knoe if there is a way to randomizze the cosnt Activation for turn off and on the Constant Activation on the pop source?
  15. POP Stepping

    Hi all! I'm currently sitting with some superbasic POP sims to brush up on everything after a long time away from Houdini. My issue is, as the title depicts, that I have problems with stepping even though - to my knowledge - this scene shouldn't suffer from it. I have three spheres as sources, they don't move at all. The top velocity of the particles peak at about 0.9 in the geometry spreadsheet, it travelled about 1.2 meters in 42 frames, so no extremes velocities exactly (or I am just very uninformed and would love to be enlightened!). I tried every combination of birth jitter in the POP Source and found very little difference, the ones displayed below became the final ones. Attaching images of my solver settins, birth settings and a render. Any and all help would be greatly appreciated! Cheers, Jack
  16. Particles opacity control

    Hello, I have finished a particle simulation using popnet inside SOP in houdini 15. I have added color and opacity information using POP color node. While rendering using mantra renderer, the color is rendered fine, but as alpha, it doesn't render what I created using POPcolor. It's all visible/opaque 100%. I want to control opacity. I have not assigned any shader yet. Please share a solution. Thanks
  17. Hello, I was following a tutorial on how to create a sun in houdini, and I came across a technique used to keep advected points bound to the original surface where they were scattered from (in this case, a sphere). For the purpose of advecting the points, it was created a popnetwork with a curl noise affecting the velocity. To keep the points moving on the surface, the instructor did 2 things: -Turn the sphere into a mesh and convert it into a VDB. -Create a POP VOP, with a Volumesample and a Volumegradient, reading from the vdb converted sphere. After this, the gradient was inverted and multiplied by the output of the Volumesample node and added to the original positions, inputing into the new positions. This last point got me lost. The instructor referenced in some abstract drawings the utility of both this nodes, the Volumesample and Volumegradient and I tried to cross check with Sidefx's Houdini documentation but it didn't have that much info on the subject. Can some one briefly explain what is happening inside both this nodes, and their respective outputs? Thanks.
  18. POP Emission

    Hi,I started houdini a while ago,I have some question about POP emission. If I wanted to start the emission at frame 1050,I would type $FF < 1050 in the Const.Activation. But,If I wanted to Emit from Frame 1050 and keep Emitting for 3 frames from that Frame,What should I do? Thanks
  19. Inside DOP cluster grid source

    Hi Friends, I need your help!! I'm playing with DOP, trying to understand it and feel comfortable working with data.. I come across one issue that I have trouble with.. Is there a way to create cluster grid inside dop? The problem is that I need to timeshift whole range to get initial data for clusters.. Here is the hip file, you can take a look.. I would appreciate some extra feedback about the way I approached with this setup.. I'm I doing something wrong? Thank you!! Regards, M in_dop_clustering_help.hipnc
  20. hi everyone. This is a short film made by ManvsMachine for Logitech This effect appears in the video 35 seconds. https://vimeo.com/245950999 (also I uploaded a screenshot of an attachment on this effect.) i want to get this effect.it look like used find-shortest-path,but it's full of details.there are small lines at the end & corner of these large lines. i’m try use pop-steer-path to simulate these details.but unfortunately, it's not very useful. Can you give me some method? be deeply gratefuls
  21. Hi all I am trying to simulate rain splashing on an already full tea cup, like the reference below. I have done a FLIP simulation which fills up the teacup quickly using an emitter inside the teacup, i have also done a basic rain simulation using the POP solver. BUT. i cant get the two to interact, the rain needs to be splashing the water as it hits it but i have been struggling for a few days and just cant seem to get it to work. I'm guessing its because i have used a FLIP solver for one and a POP solver for the other, but i have tried making them both FLIP or both POP but i just cant seem to get it to work with either. I don't know a huge amount about particle simulations so i might be being really dumb here but can anyone give me any advice or spot anywhere where i have gone wrong? I've attached the scene file and the geometry .obj that needs reading in, along with some screenshots of my nodes. Any advice would be amazing! Thank you in advance! rain_issues.hipnc teaCupV3.obj
  22. POP Flock Orientation issue

    Hello node friends! I'm diving in flocks.. I can't find any source of material to learn this besides a super old tutorial from cmiVFX. I was looking to create a bird flock, so far so good. Scatter a bunch of points, create a curl vel force and add a pop flock. The struggle I'm having has to do with point orientation, I can't seem to orientate the particles according to the direction they are facing, and since this is a simple bird animation, I can't find a way to make them behave properly. Does anyone know a good workflow for this? Pops or crowds? Have a good one!
  23. hi everyone, i am trying to slide particles in the inside of a geometry (a polygon box in this case) i want to get the particles freely slide along the walls (or even come on and off the walls because of the popattract force), which i managed to do with the two nodes popcollisiondetect and popproperty, however it doesn't quite slide... it goes past outside the box. especially if i increase the popforce amplitude. to keep them sliding (and inside the box) i have to raise the "cling" in popproperty node to very high value which almost makes them look stick rather than slide. However, a sphere instead of a box works fine.... the pighead somewhere in between the box and the sphere. anyone knows where i should tweak things? FYI the settings for dopnetwork is same for all the three images (1a,1b,1c) I would appreciate any help. PS: BTW how do i i make the quality of a simulation more precise (increase steps per frame) globally. m.
  24. Mesh Trail Clothlike Effect

    Hey fawkes! Any Ideas on hot to achieve something like this? Been thinking about using some emission group with a POP and some trails. My doubt is how to mesh the stuff and give it the subtle cloth dynamics. Maybe a Geometry or Point Vop with a noise. How about UVs here? Any Ideas? Cheers!
  25. Emit RBD objects

    Hey guys ! I recently followed the "Houdini 15+ Particles to Bullet" tutorials from Andrew (https://vimeo.com/179143928) and then the "Emit Bullet from Particles" tutorials from Tim van Helsdingen (https://vimeo.com/179639085) but I've got a weird issue that I can't figured out. I strictly followed what they show on their videos, but, when I'm checking my RBD sim, I have duplicate geometries on my point (as you can see on my screenshot). Also, the bullet solver warn me by this message : Something has changed in the RBD between H15 and H16 ? Am I missing something ? Thanks in advance guys, Gael. PS : Here's my file, but it's normally, as we can have in Tim's video. emit_rbd.hip