Jump to content

Search the Community

Showing results for tags 'pop'.



More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


Forums

  • General
    • Lounge/General chat
    • Education
    • Jobs
  • Houdini
    • General Houdini Questions
    • Effects
    • Modeling
    • Animation & Rigging
    • Lighting & Rendering
    • Compositing
    • Games
    • Tools (HDA's etc.)
  • Coders Corner
    • HDK : Houdini Development Kit
    • Scripting
    • Shaders
  • Art and Challenges
    • Finished Work
    • Work in Progress
    • VFX Challenge
    • Effects Challenge Archive
  • Systems and Other Applications
    • Other 3d Packages
    • Operating Systems
    • Hardware
    • Pipeline
  • od|force
    • Feedback, Suggestions, Bugs

Found 102 results

  1. 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.
  2. 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?
  3. 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
  4. 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
  5. 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.
  6. 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
  7. 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
  8. 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
  9. 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
  10. 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!
  11. 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.
  12. 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!
  13. 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
  14. Hi gang, I was just scratching my head over how to get my popaxisforce object to follow the emitter I want to affect with it. It's basically a geo group that defines the emitter surface (jet engine thing) and shoots out particles behind it and I want the popaxis force to follow close behind to manipulate the particles. I thought maybe object merge in the dop network would do the trick but it's doing some pretty weird stuff instead like creating a duplicate emitter that follows the jet's animation/xform but offset in time. Any insight would be great, thanks! jet_emitter_popaxisforce.hiplc
  15. Hi, I'm pretty sure this is a simple question but i can't seem to solve it. I want some particles to emit between a certain number of frames and again start and stop in different frame number. ie for eg :- Starts from 1 and stops at 10th frame then again start from may be 15 to 20 What would be the expression for this, i'm using "$F >1 && $F<10", it works, but then i don't know how to get them to start again from 15 and stops at 20th frame. in the same . This is for Impulse Activation (in POPnet) Any help would be really great. Thanks
  16. Pop sprite Problem

    Hi Guys I got a problem with pop sprite, I set a sprite rotation on my particle sim, I use rand(id) to make every particle rot differently but when the particle hit on the ground, the spriterot attribute keep going, so that it keep rotating on the ground when I assign a sprite texture, so is there a way to make the particle stop rotate once the particle hit on the ground? thanks a lot for your help.
  17. Hey magicians, I'm learning about velocities on particles, I made a shape that drives the velocity, but the particles are going diagonal instead of straight (the actual shape animation is just a vertical movement). I can't figure out whats driving this, I don't have any forces, any help will be great. Hip attached Thanks! particles.hip
  18. Granular Sheet - Moving Pin Constraints

    Hey everyone, after unsuccessfully scouring the web and the two big Houdini forums I finally brought myself to asking directly. I'm currently trying to animate a sheet of cloth using a granular sheet since the FEM approach is just excruciatingly slow. I've found three methods for pinning parts of the granular sheet in position (@stuck, @mass = 0, @targetP) but I wasn't able to find a use either of these methods for an animated pin constraint. I'm obviously still not really proficient in Houdini since this problem has me completely stumped. So if any of you lovely people would point me in the right direction, I'd be immensely grateful. Thanks in advance! *edit: After searching some more, I came across this thread: While the file attached to the thread works when I play it, when I try to copy that setup into my scene, it just refuses to work, even though the @targetP gets updated. Obviously, I'm doing something wrong but even comparing the node settings side by side I can't for the life of me figure out what that something is. *edit #2: Okay, I finally figured it out. I didn't realize that the sop solver node is empty by default and you have to create the sop structure to update every frame by yourself. Now that I've figured that out it is perfectly reasonable, I just didn't think of that for quite some time. dia3_dmo_001_010_cgfx_setup_v003_pj_stripped.hip
  19. Loop Particles for Geo Instances

    Hi everyone Wonder in knowing, I am trying to get a kind of loop particles systems, means that when they collide with an object, will recover back their original position and re-simulate creating a loop. Main constraint here is that ptnum must to be constant, cannot die. After this it would allow to set different conditions as reboot when leaves frustrum or after a certain initial age, etc. My only issue is that I arrive at update (in the wrong way for being honest) the velocities to re-do the sim cycle, just that goes in the worng direction, exist a way to make them restart with their initial velocities, attached a HIP file of example. Thanks LoopParticlesTEST.hip
  20. Hi Odforce. I have POPs moving past a point and I want the stream to inherit and keep the points normal after passing. I thought this would be a straight forward pcopen() case, but I cant get it to keep the normal. It's only there for as long as it is within the search radius. I've tried a few different things in vex. wrapping it in an If statement instead of while, but to no avail. Edit: I should maybe mention that I'm in SOP right after importing from a DOP. Tried to make it work in POP wrangle but had no luck there either. Thanks, Bastian
  21. Hey magicians, Been fighting with this pile setup for a couple of days, I need to make a candy pile, I'm using grains but when I replace the geo there are some artifacts like the geo is inside the particle and leaves weird holes, anyone knows how this can be fixed? It need to be the more realistic way possible @f1480187 would love to hear your thoughts sensei Thanks pile3.hip
  22. RDB driven by POP network

    Hello! Firstly, I'm very new to Houdini (coming from Maya), so I apologize if this has been posted before; when looking for a solution I may have just not searched the correct terms. At 49:00 in the below video, Jeff Wagner demonstrates an RBD solver that is 'driven' or on some level involves a POP network. I want to achieve a similar effect. I currently have a shattered object (using another tutorial to create jagged voronoi). Additionally, I'd like to scatter points along the inside point group (from shatter) to create wires, Entagma recently released a tutorial that I can probably use. Getting curves that are affected by gravity would be a perk, but it might be beyond ability trying to make them dynamic constraints to the shattered pieces, etc. If I don't do this however, I might have an issue with them clipping into the geo. Thoughts on how to make them collide-able at least would be appreciated. Would love anything to point me in the right direction. Thanks!
  23. I'm currently following along with Rohan Dalvi's Motion Graphics tutorial, and I've run into two issues with the particles from the outer ring that I thought would have simple solutions, but so far have completely stumped me. The first thing I've found is that each point would spawn two particles, resulting in two lines very close together, and I want to get only one particle/line for each spawn. I've figured out the reason for this happen is that in my POP network I do two separate replicates, each on a different particle stream/group (so that I can have differing life lengths), and the replicate POP passes through the original particles (even those no being replicated) so after merging the replicates back together, I end up with two separate sets of the original spawner particles. Now the solution I came up with was to remove the points I didn't want to replicate, do the replicate for each group, then merge them back together (exactly like I would if I had this issue in SOPs). Problem is though that didn't work at all. I tried both Kill POPs and POP Wrangles, and a few different setups but nothing worked. I've included some notes with the scene file to give better explanations. Secondly, when the spawner particle collides with the tube, the replicator keeps replicating it, so we end up with a bunch of points stacked on top of each other, which I don't want. My idea to fix was to have a node placed straight after the replicate that removes any particles in the "hitparticle" group from the "stream_General_Spawner" group. That way, on the next frame, all the collided particles won't be replicate again. But this didn't entirely work either. "Combine Groups" on the Group POP almost did the trick, but in addition to removing the particles from the spawner group, it also removed them from the hitparticle group, which I don't want because I have a wrangle that does stuff with that group. Does anyone know why these issues exist? I'm guess that I'm missing some sort of foundational knowledge on how POPs work? Any recommendations for tutorials or articles to go along with the documentation to help with this? POPs_problem.hipnc
  24. Hi, I'm trying to replicate the way you can set color for a particle's "initial state" in a Maya particle system. I've looked through docs, tuts, etc, and have not been able to get this to work: Here's what I got so far: ---------------------------- I've scattered points over some terrain Geo, used a point Vop to create noise based color for the Cd attribute on the points, then used the points as the initial geometry in the popObject. The idea is to have textured "dust" blow over the Geo (I'm driving the pop animation with a Pyro sim). The animation works well, but I can't figure out how to transfer the Cd attribute of the scattered points to the particles. I played with creating the color with a PopVop in the Dop network, but the color is assigned by position so the particles animate but the color does not. I've attached my test scene. I'd appreciate any clues; thanks in advance bcs_partDustTest_v01.zip
  25. Copy Debris Mesh to Pop

    Hey guys, Does anyone knows how can I copy these debris into the Pop Simulation points? (Scene file is attached) copy.fragments.to.particles.v1a.hiplc
×