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Found 148 results

  1. Dust effects

    Hello, I'm trying to make dust effects like Avengers. I used color attribute by boolean and use pop with it. I'm struggling with generating pop and there is some lagging like the video I upload. How could I fit it and makes it looks right way of emitting particle as well? untitled.mov dust_effects.hiplc
  2. I am doing a small rain system. When i add the trail sop, followed by an add to connect the point with the ID attribute, everything works fine until i set the trail increment to a value different than 1, then it completely breaks. I believe it is because particle are dying, but i cannot figure out how to debug it Trail_sop_issue.hip
  3. Fluid into FLIPtank + interact

    What I am trying to do is to get a fluid of any kind (pop or flip presumably) to interact with the fluid in a flat fliptank. Seems like it should be easy, but I can't seem to get them to react and mix like fluids (or interact at all actually). More detail: I actually am trying to get a cloud of blood to spread out into a pool under a body that has just fallen in. Perhaps this means I need a different solution than if I was dumping particles into the tank from an emitter outside of it, but I can't even get that to interact, so any advice on this would be most helpful, and I am grateful to anyone who spares even a moment to consider the problem. Much appreciated! PS- I have scoured the internet, including this site, for advice on this, and have come up empty handed.
  4. CONFETTI PARTICLE FORCE

    how can i create this effect in houdini. basically i need to know "how to make this particle sim" if possible please make a file for me. Effect is video reference in this link: 11 sec . https://vimeo.com/172598946
  5. DOP to POP

    Hi guys! Just looking for a little bit of help, to see if what I am trying to achieve is actually possible and if it is maybe someone could assist me in figuring it out! I have attached my file below, I am attempting to make a Volcano react. This is the reference I am trying to copy to the best of my limited abilities! https://www.youtube.com/watch?v=9Plj4b79cwg My question is in regards to the node named SIMULATION, ignore the first DOP for the first smoke. I am working on the out put from the lava, now everything looks horrible, but I am trying to get the set up to work so I can edit things all at the same time (Uni assignment, short time frame, was recommended to do it this way.) Anyways I have the 'Lava' moving kind of how I would like for now and I now want to take the movement of the lava and turn it into particles to put into a POP to create small particles/sparks. I am certain this could be done. But I cannot wrap my head around how to achieve it, I got it done for the secondary smoke from the lava plugging the output into a pyro, which I haven't edited yet so that reaction is a bit of a mess. But I want to figure this out before moving on! Any help or recommendations would be hugely helpful! Or even if you know of any tutorials that walk through this? As I haven't come across any.... Thanks! Assign07e2.hipnc
  6. Hi guys! I have a problem that's been bothering me for a couple of days and I can't seem to wrap my head around to solve: I have a grid, with scattered points. And I have 3 objects hovering above the grid. With a colour shift on the grid (attribute transfer with an animated ball for now), I "activate" the points in a pop network, and I start adding forces on them, choreographing them, until they reach a certain age and start to move to the 3 objects above, like an attraction (point count is the same in both inputs for simplicity - also I have colour grouped which particles belong to which object for visualisation purposes). So far so good. The problem is that in theory, each $id should correspond in each point on the objects above - but alas, they seem to shift groups! So, instead of clean motion / attraction on each of the objects after a specific time, I get more of a random mass of particles moving back and forth the objects until the end where they stick on the objects. There sure is something wrong with my vex, but I cannot understand what! It should be easy: green goes to green, blue to blue and red to red.. Attached are some images to help understand the problem. the viewport describing the problem: the pop hierarchy: the wrangle to move the points to position after a certain amount of time in the "time_in_release": If anybody has any idea as to why this is happening, please, feel free to share! I would be more than grateful to hear your thoughts! Thank you so much for your time, G.
  7. growing line effects

    Hello, everyone. I'm trying to make the growing line apart from object and I have few problem. So far, I made growing line from object and i would like it to move away from the center which means that the center of pop generation is too high density. However, I keep the speed as slow and I just want wires (I generated it by pop and use vdb so, looks like wire growing) go away from center slowly, so looks center less density. Sorry, my explanation is too bad since I'm not native speaker, but hopefully you guys understand what I said by file I attached. And, if you know good way the wire looks sharp, please help me. Thank you. grow_wire.zip
  8. Packed RBD from Pop Sim

    Happy Friday, Trying to wrap my head around constraining or copying packed rbd's to particles that are moving along a surface. Attached is my test scene please help if you have time! Thanks, particleRbdTest_01.hip
  9. Flip Sphere Motions

    Hey there, I'm trying to replicate this setup: Liquid Sphere Based on my scene, I have a sphere and the particles are generated from it with iso offset and particles from volume. Within FLIP, I tried to control the velocity with pop forces (POP force, pop attractor and pop axis force) and got somewhat of a swirly motion but the in the reference video, towards the end you can see the fluid is ground around a torus like motion and the shape as well Any pointers on achieving this? HIP file attached included. Thanks! SH02_Water_v02.hip
  10. Hello everyone, I've seen multiple posts and some discussion on regards to sprites, but most of it is from 8 or 10 years ago, so I was wondering if anyone would have some insight on a workflow or an example on H.17 for adding a looping image sequences to sprites. You must be thinking, "sprites? people still use those?", but the style I'm aiming to achieve relies heavily on some 2D animation. I've used some techniques with traced 2D sequences instanced into particles but for the sprites I am a little lost, specially when it comes to rendering the sequences. I've created an attribute for it based on the life $HIP/Sprite_v001_`padzero(4,round(fit01($LIFE,1,20)))`.png but not sure where to use it afterwards (shops have changed a lot in recent years). Also tried adding something to the Sprite Map on the popsprite inside dop: $HIP/Sprite_v001_`padzero(4,$F%40+1)`.png but still no success. Any help would be greatly appreciated.
  11. Hi, I'm a beginner in Houdini learning alone with tutorials, I need some insights about POP. What I'm trying to achieve: I want to reproduce this effect, but slower: Basicaly, I have a polyline forming a shape, I scale each primitive in a foreach loop with x iterations. Each iteration go through a DOP Network with a different seed based on the index of the polyline in the for loop. The DOP Network move points with a curlNoise, I then create a trail. The screenshot shows the effect on a single instance. Questions: 1/ I can't access the Birth Parameters on the POP Source node. From the help, it seems "Impulse Activation" at anything but 0 to be able to access those settings, but it's greyed out. Am I missing something? (It's greyed out even if I input "1" and not an expression.) 2/ To get a lower number of points, I used an Impute Activation of (($F%20)-1)*-1 == 1 point every 20 frames. The problem is that now, the DOP network does not begin before $F=20. Is there any other way to tell POP not to birth points every frames while being able to choose the first birth frame? 3/ I want each point created in DOP to keep as an attribute his original position (when his age was 0), and I want each new point to keep @ptnum of the source point as an attribute. How can I do that in DOP? Thanks!
  12. Hey Everyone! Is it possible to define a region (perhaps with a shape) which pop forces are applied. I have an rbd sim and am looking to have a specific area that is affected by a pop force. Any ideas? Thanks
  13. Particles will bounce off a collision object, and I can influence that using the collider's Bounce parameter. Great. However, if I change my particles to grains, they will not bounce anymore, but slide. No matter what I do and this goes for pop grains as well as for Vellum grains. Settting ispbd to 0 is not a real solution, as this means I am not using PBD/Grains, anymore. Any idea? Here's a very simple test scene, using a pighead. Just activate/deactivate the POP Grains node in DOPs. collision_grains.hipnc
  14. kill pop force contribution on Y

    hey! is there a way of limiting or killing the contribution of pop force in an axis?
  15. Hi, In my popnet, I want that, a new particle is born only if there are no particles in the scene. That is, suppose a single particle is born and dies after, say some random frame, only then a new particle is born. No new particle can be born even if a single particle is alive. How can I do that? Please help Thanks @Alain2131 : Sorry to tag you here, I just wanted some more help. Please let me know if tagging is not permitted or if you are bothered by it, I wont tag you again.
  16. Hello, I have an object what I broke with an rbdmaterial fracture then I feed the points into a popnet and add some stuff like wind to move the points. My question is: How can I reset or rebuild or move back the points into their original place and shape like a fast rewind or something. Thank you
  17. Underwater Bubble Sim

    Hey guys, so basically I'm trying to replicate an object dropping into a tank of water splash but with the bubbles/water only. The way I'm currently doing it is by emitting particles based on emission attributes defined on the surface based on it's velocity and using vdb from particles to mesh the liquid and so far it's alright. However, the client wanted a more art directable look towards the pop sim whereby more lengthy/streaky bubbles instead of huge splash etc and it got me thinking how can I achieve this? I'm on H16 and there's no pop fluid where I can easy increase the surface tension and viscosity to save my shot. Is there any pointers on hacking this shot without doing Flip? I'll upload my WIP, files and other references from client tomorrow. Thanks
  18. Duplicate objects in RBD pop net

    DOP net question. I want to start with a set number of boxes and have them move around with POP forces and bounce off each other with RBD. Problem is that I end up with two items for each one I put in. For the POP source I setup Impulse activation to be $F == 2. If I use 1 there, I only get one set of items but they aren't effected by the POPAdvect forces. Feels like a rookie mistaken, but I not sure how to set it up. Any ideas? POP Source: Emission Type is All Geo, Geo Source is First Con text RBD Vector Field.hipnc
  19. hey everyone, I'm struggling with a problem. Here, the particles move randomly. I would like them to become visible when they pass through the cone until it comes out. I don't know how to proceed, I tried a few things but couldn't get something to work. How should I create the collision attribute and apply it to my attribute vop ? Could someone help me or guide me a bit, please. Thanks particule_collide_dust.hipnc
  20. Hey all, I'm trying to get a better grasp of best practices for managing substeps between two separate DOPnets. I have a DOPnet that takes in moving geo and outputs particles, which I rasterize to a volume, then source into another DOPnet as fuel, temp, etc. for a pyro simulation. What I'm wondering about specifically is how to keep these two DOPnets in sync. i.e. I want to make sure only newly generated fuel is sourced into the pyro sim, not fuel that's already "burned". My concern is that if the POPnet creates particles with life longer than a substep on my pyro sim, they will be copied into the pyro multiple times. It seems like it would be best if the particles and Pyro were created in the same DOPnet? I don't know enough about how any of this works though.
  21. Custom attract

    Hi I am trying to create a custom attraction tool using popvops. Its a method I learnt doing a houdini course I would like to improve on it but I have been stuck on it forever. Instead of using a pop attract we are using a popvop to calculate the distance of the particles to a point in space and making them move to this point, if I am using a single point to attract them to its working fine, but what I would like to do is to attract them to multiple points ie a mesh. I have tried using the importpoints but that just makes them go to origin. I would like them to move to the rubber toy. Any advice would be appreciated. I have attached the file and the particle stream I am using to test. Cheers Particles.72.bgeo.sc attraction test.hiplc
  22. I have a feeling this might be a dumb question, but I have been stuck on it for a few days now. Or maybe not so, as I've been looking countless treads here, but none really solved my problem. I've got a really simple setup, pop curve force guiding some rbd objects (I also tried doing it with points and copy stamping after sim to the same result). At a point in the sim the vectors start to point outwards: What I would need is for their direction to be always facing forward as they are at the start: I've had some luck with using pop torque, but still not what I need. I've attached an example file and the curve alembic. RBD_Directional_Vectors_Curve_Force.hip curve01.abc
  23. Dear community, I am working on a little particle system that I need some help with and I hope that you can help me out somehow: I am emitting particles from points A. These particles are attracted by another pointcloud B via POP Attract, with the attraction type set to points. So far so good. My question is now: How can I vary the attraction force inside pointcloud B for each point? Is that possible? I've been looking into and reading the docs, of course, but all to no avail. Does anybody have an idea on how to solve this issue, meaning giving the points in pointcloud B varying attraction forces? Is there an attribute that I have to apply on pointcloud B, that POP attract could use? Best wishes and merry christmas and Chanukka, Nicolas
  24. I am trying to blow up multiple groups of particles in a sequence.(boxes of confetti exploding at different times). The activation isn't really the problem as I can use a sop solver within a dop to activate the particles group at different time. The issue is to give them that "initial velocity" at activation time. The only method i found that is working to achieve the effect, was to actually import and merge many popobject and "activate" them one by one in a sequence , with the velocity attribute created at sop level This solution is of course very inconvenient. I attached a clean file, with just the different group all popping at the same time. a solution to have them delayed one after the other would be very welcome I just can't find an elegant method which works procedurally. Thank you for your help confetis.hip
  25. **I'm amending this--originally it was just the below question, about making POP particles collide with FLIP sims, but I just was toying with multiple POP emitters/particles in the same scene, and they don't seem to want to play together easier--so my more fundamental (surely stupider) question is: how does one make different particle systems (POP, FLIP) interact? For instance, in the supersimple screenshot, I would want the orange particles (which have initial velocity on x) to collide with the blue ones. I would think, since they're part of the same POP solver, this would just happen. I would think wrong.** I have a puddle of bood, a viscous FLIP fluid. I have POP particle rain (a la https://www.sidefx.com/tutorials/rain-systems-and-wetmaps/). How can I make the rain (the particles--I assume not the instanced geo) collide with/splash the FLIP fluids? I understand how to use POP forces on FLIP sims, but when I put a POPnet and FLIP sim in the same scene, they just ignore each other. Since static/RBD and particle (FLIP or POP) solvers all play so well together with minimal extra effort, I'm sure getting POP and FLIP sims to play together is something simple and dumb. Thanks!
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