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Found 351 results

  1. Hello Houdini Magicians, This little bit of code is, according to the performance monitor and some debugging, slowing down my simulation... alot. Specially with a high number of particles. The nPt comes from the nearpoint function. I analyzed the performance impact of the nearpoint function with many particles and it is not significant. Its the conditions and moving/removing particles from groups. What is the optimal way to do this?
  2. Hi there, A bit of a noob question so I apologise for that. I have a file attached with a basic particle system, connected to a copy to points, and a grid with a png image sequence as the particle geometry ( 12 frames long ). Everything is working well, except I cannot figure out how to start the image sequence on a per particle basis. All the particles start their animation on frame 10 simultaneously and new ones born after that just start with the last hold frame. I have this - " Star Sparkle_`padzero(5, clamp($F-10 ,1 , 12))`.png " in the texture field on my principled shader and this seems to give me a 10 frame offset, and it holds the first and last frame, instead of turning into a white grid, which is great. But how do I get each particles animation to start at it's birth or at an offset from it's birth time/age/frame ? I've included the required png sequence with the file. Thanks to anyone who can help me with this, it's making me feel very silly that I can't figure it out in over a week. Have a great day ! Sprite Particles.7z
  3. Hey wizards! So I'm working on a project and I'm tasked with doing an inverse whirlpool. I've tried several techniques like curve force and axis force but they become unstable and don't give the desired effect I need. I'm currently using pop particles to affect the flip and it works, but it continues to grow then it becomes unstable. I'm trying to recreate the effect in the pokemon video but I need it to run for a long time without being unstable. What would be my approach to achieving this effect? Here is my hip file that I'm working on, maybe someone can notice if I'm doing something wrong lol water swirl.flv smalltornado_unstable.mov smalltornado_unstable2.mov watertesting_forum.hiplc
  4. Hello good people, Let's say I have a particle simulation, I would like to store the position of every point at the starting frame and then later on, say frame 25, I'd like to reevaluate each point position. If the new number is different than that on frame one, ie the particle moved, something happens to the particle, it stops, turns green, whatever. Basically some kind of if statement, if newVal != oldVal: turn green Any help is welcome!
  5. Alembic particles to C4D

    I spent a fair bit of time trying to figure this out today so I figured I'd post a quick tutorial for posterity. The only other guides and info I could find were specific to getting pscale and Cd into C4d for Redshift. Nothing on orientation or other attributes generally. Long story short: - Unless your attribute is explicitly typed (i.e. Vector, Quaternion, Matrix instead of 3flt, 4flt, 9flt) C4d will read it as a float (or "Real") - Orientation is handled by the "Alignment" TP channel, so you need to convert your @orient to a matrix3 before export Hope this saves someone else some time.
  6. Hello; When I use scattered points as a POP source, how can I apply velocity to some group of points, dynamically ( during frames, not just at the initial frame)? I know that I should apply the velocity force inside the DOP, but I don't know how Thanks for helping. Add_Velocity_to_particles_01.hip
  7. looping particles

    I have been looping particles using CGmonkey's method: Once I raise the particles to something high(500000+) the particles start to freeze and stutter towards the middle. In theory they should all loop together, but for some reason they are not. I'm looking for a way around this or any help with looping high numbers of particles. Thanks. torus_particle_loop.hipnc
  8. Hello! I'm doing a school project, and I have to create something like a slime mesh. The main problem I have, is that I get a lot of flickering when I try to mesh the vellum grain using the particle fluid surface node. The same thing happens when I'm trying to mesh flip particles. Does anyone know how to get rid of this flickering? I've been searching a lot but can't find an answer. Thanks!! StickyFluid.mp4 bloodRND.mp4
  9. Flip Fuid Volume Loss

    Greetings, I'm doing a basic flip simulation where I fill a cup with liquid and then I rotate the cup to spill the liquid into another cup. Sounds super easy and basic, but after some time fine-tuning the collisions and the liquid I can say with certainty that my liquid volume is getting less and less like my particles are dying or sucked into the geometry. A searched a lot for a solution, like changing the Scale of the scene, or lowering the Grid-Scale ( CG Wiki ), or change the collisions but nothing really helps at all. thank you in regards
  10. How can I render my particles with the isotropic volume lighting model and get self shadows? Its like there is no occlusion and I can see my particle field from one way to the other side, and I can't distinguish wich are in front and wich are in the back... Cheers, Diogo
  11. Are there any good resources on rendering particles with Karma? And does it support micropolygon rendering? Thanks
  12. With fast moving collision geometry and FLIP, what are some things to try to stop fluid from passing thru your geometry? Things I've tried - increasing substeps (using 8 currently) - reducing particle separation (I'm at .01 currently) What else should I try?
  13. Hello everyone, I'm trying to emit RBD objects from particles but cannot get it to work. I've watched the tutorials from Tim van Helsdingen, Matteo Migliorini and Andrew Melnychukk, but I cannot get it right. I want to simulate banknotes flying in the air with some swirling and self-colliding. Some tutorials use a bullet solver, the newest one a RBD solver. Both setups give me strange effects. Bullet does nothing and with the RBD solver my bank notes just explode up in the air. And some of my banknotes sometimes stop moving or disappear. I've attached the two setups, maybe you can point me in the right direction. Thank you very much Emitt_to_RBD_Bullet_Solver.hipnc Emitt_to_RBD_RBD_Solver.hipnc
  14. Hi! I am trying to do simulation using crowd system. Agents should decide wich 1 of 3 splines to choose depends on smallest popgroup number in destination point. Could anybody help with VEX in popwrangle? Hier is a scheme attached. I think to use splines because houdini has not navmesh like unreal engine has. And navmesh as far I know just splits polygones and draw optimal spline on its chunks in direction of movement. This should simulate 3 lines in a shop. Agents should go where is not to much people waiting
  15. So I've been looking for some time on the internet how to do this seemingly straight-forward thing. I have a pretty simple particle sim with a copy to points to attach a plane to each particle. Particles move a little with a popforce inside a pop network and thats it. I want to export this simulation into UE4 with the plane attached to the particles. I tried: - The gamedev "rbd to fbx" node and try to make it work with particles, I couldnt make it work. - Export it as FBX, in Maya it works but in UE4 it exports it as a Static Mesh. I wanna know if theres a way to export the particle sim into UE4 so I can use the planes to attach any texture I want. Theres an image for more context. Also if theres a way to bake the simulation as an animation with keyframes or something like that (not cache to disk). Thanks in advance!
  16. Hello everyone. I'm trying to emit particles from a rubik's cube which are solving himself. The problem is it doesn't look appealing because the emission is everywhere and without variations. I would like to emit the sparks only when the cube is rotating and only on the side of the rotation. Do you have an idea on how I could achieve this ? rubikSparks_01.hip
  17. Explosion timing methods?

    Hi all, Going to get straight to my point here. I've been trying to wrap my head around a proper workflow for achieving good timings explosion and smoke simulations. Let's say in this example explosion , the look and the timings are great. My ideas are either having proper advection methods, using animated divergence, injecting high velocities for first few frames and then using drag to slow it down or (last idea I had today) using Time Warp node, to retime the whole explosion caches to your preferred look. Could someone experienced enough drop a few lines around what the approach of an FX artist is whilst tackling a explosion in a shot for a film or just in general. Am I going down the right path with these methods or is it completely off? Thanks
  18. Opacity from Attribute Transfer

    Hello, I have having trouble with a particle effect and I can't find anything on how I would achieve it. I have a rough idea of how it might work but my houdini knowledge and experience isn't good enough to actually do it. I am trying to create the effect of an illuminated object flying through a room full of particles, like dust in a warehouse. I want the particles to initially be invisible and only when the target object passes by for the particles to become visible and then begin to glow. So far I have a set up where the target object flys through the scene and collides with the particles. As it does this I have an Attribute transfer that gives me a field of influence that I want to drive the visibility of the particles. Does anyone now how I could do this? ParticlesTest_v032.hip
  19. Peter Claes - Youtube channel

    Hi all, As some of you may know I have recently started a youtube channel where I am sharing some techniques, setups and tips. My goal is to first cover some of the fundamental tools/setups and then build more elaborate setups. I wanted to share this with the odforce community too as this community will always have a special place in my heart :). Thank you for watching & have fun learning! The channel: https://www.youtube.com/channel/UCZMPkkgnAFghvffxaTh6CsA My first video:
  20. 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
  21. Grouping points in cached FLIP sim?

    I have a pre-simmed/cached FLIP sim. I would like to create a group of a section of the particles of the sim so I can mesh them separately and apply different shaders to them later. Re-simming is difficult and slightly impractical, so I would love to be able to do this with the cached points as-is(/are). I can create a group of points, but it looks like point numbers are not constant in FLIP sims, as the group changes over the course of the sim (frame to frame, actually). Is there a way to create a group that then remains constant and flows with the existing sim? Or even a way to create a new group of particles that is advected by the existing cached sim? (I'm pretty sure it's no longer a "volume" by then, so I'm guessing a straightforward advection by volume POP wouldn't work.) Or a way to do some sort of "sort" operation to compel points to retain point numbers, which I could then group? Or advecting another form to follow the sim, and I could then use that as a bounding volume to create my group? (Point deforms with FLIP sims as the deformer seem to get really messy really quickly.) Thanks for any help!
  22. 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.
  23. Issue with pyro emitted from particles

    Hi everyone, I'm trying to create an effect similar to a roman candle (similar to this https://www.youtube.com/watch?v=MVtGNNcTjEE&feature=youtu.be&t=169 ) So I created some particles shooting up, and wanted to emit pyro from it. Everything works fine but I have an issue I can't fix. When a particle dies, a trail of smoke appears between it's last position and all the others particles. Someone had the same issue ? I tried all I could think of but did not find a way to fix it. Thanks
  24. Hello, I have a question but I haven't found away to solve it , I want to instance soft bodies to a particle system that is constantly generating particles (constantly changing the numer of particles). That could be with FEM , grains or vellum you name it. which would be the best approach to do that, so far I faked the effect with the analytic foam tutorial on Entagma, but yet it is missing a lot of the motion I am looking for. Thank you for your help!
  25. what is a pscale attribute in houdini and how can we use it?
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