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Found 195 results

  1. PARTICLES MOTION STOP

    HI, I know this might be an easy thing but i tried out and seems like i'm making a silly mistake. How can i make the movement of particles stop as it slows down?
  2. WATER DRIP

    Hi, I've been trying to make particles slide down a vertical surface but I want them to stop for a second while in motion, and then continue sliding again. I guess, I badly need help with this. Can anyone help me out ? I've tried animating the response feature in POP Behavior Detect but didn't work out. Each particle should have its own movement. Regards, David
  3. Hi, I want to emit particles from an texture just like in maya. I find the old thread here : but in houdini 16.5. That seems not work. . there are no " birth probability ",but "emisson attribute".And it says that it will use a point attribute.(but this will need very high mesh resolusion.) I fill the pic function in it ,but it returns an error. How to do this ? Thank you very much.
  4. Recursive Particle Split

    Hey guys, how can I duplicate particles recursively? Sort of in a fractal / l-system way, to simulate veins, bramches and stuff like this Thx
  5. Hello there, Is there any way to create Geo dynamically inside a dopnet? Specifically, i would like to have growing tendrils, and simulate those as they are created using popgrains. I created a popwrangle inside my dopnet, and created new points and primitives through vex. Unfortunately, that breaks the pop solver, as its not solving the newly created particles (However, if I put a force after the popsolver it works). I thought maybe that resetting the id to -1 (as used in a similiar way with the bullet solver) would do the trick, but unfortunately not. Is there any way that I can force the popsolver to recognize those newly created particles? Thanks in advance, Bajt createGeoinPop_v01.hiplc
  6. Points follow points

    Hello everybody! I would like to simulate particles on top of pre-animated / pre-simulated (cached) points. So far I only managed to do the "transfer v attribute inside a sop solver" trick. Unfortunately it does not give me the result I imagine. Instead of inheriting only the velocity I would rather like the points to be attracted by the pre-animated points so they tumble around and follow them the animated ones. Basically I am trying to animate some points and then do a simulation on top of it to give it a more natural feel and to be able to art direct the simulation better. I would greatly appreciate if somebody could give me a hint or a solution on how to do that? Thank you! Here is my current progress (particles inherit v): pop_transfer_vel.hiplc
  7. 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
  8. 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
  9. 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
  10. 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
  11. 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
  12. 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 ?
  13. 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
  14. 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
  15. 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!
  16. 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
  17. 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?
  18. 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?
  19. PARTICLES BEHAVIOR

    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.
  20. 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?
  21. 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
  22. 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
  23. 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.
  24. 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
  25. 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
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