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Found 442 results

  1. Rocket exhaust - Particle based pyro simulation

    Hello folks, I am trying to re-create the "rocket exhaust expansion effect", when a rocket goes up and the flame is expanding because of the thiner atmosphere.. I have now 2 particle simulations, which are my main source for my pyro simulation.. but when I attached a pyro sim to the particle sim, then there are small flame points: as seen on my screenshot.. (it was rendered with Blender, Cylces)... and it also looks that ugly in Houdini... how can I achieve the wanted effect like on the reference picture: and how I need to set up my pyro sim, so that these dots will dissapear and will get visible as a seamless flame like on the reference picture..? - I have tried to add substeps but But the main thing is, that I am following the SpaceX Starship programm, and there will be a much bigger Rocket with more engines... And now i am wondering how can I create this massive flame which will be produced by this massive rocket... I have attached 2 images, and 1 video, where I am showing my current particle simulations: one image my current simulation... the other image is the reference image... and the 3rd image is the problem which I am facing right now... I would really appreciate some help from this community, thanks in advance Daniel 2022-05-11 14-03-50.mp4
  2. Hi, I'm kind of stuck with something I'm trying to achieve. If anybody could point me in the right direction, that would be fantastic. I'm trying to combine two techniques in the same shot. I have an image that drives a flip simulation. Image has two colors and each color will become a different fluid that interacts/mixes with the other one. Initially, this image was still and it was easy for me to achieve that with attributesfrommap and mapping Cd to viscosity and density. Now I need the underlying image to be an animation (only the character moves, the rest is still). I got the character animation driving the particles representing its shape using the volume optical flow technique. However, I'm struggling to find a way to merge these two systems together and basically add the character movement to the fluids mixing together generated from image Cd. This is a test project folder, which includes the images to drive the sim. motionFromAnim.zip
  3. Hello, I have been trying to recreate the black hole effect from the film 'Eternals' for a few weeks now for a thesis project I am doing and I am not really getting close. This is the effect in question: Arishem's FInal Judgement The effect happens at 1:17 My approaches was to create some circles with an animation spinning around the circles driven by the curveu attribute and offset by the 'copynum' attribute I got from the copy and transform node. I was driving a smoke sim from this and then I used the curveu as a temperature attribute to drive some scattering in the pyro shader. However this approach has not really gotten me close. I realise its quite a complex effect but any tips on recreating it would be fantastic! Thank you for reading
  4. Hi guys, I am trying to emit color smoke from a shell. I thought a good particle emission will help with the volume source from which I can emit my pyro. But, I am currently stuck at one stage where I am unable to get a nice and smooth particle flow. A lot of stepping!! I've attached the images, the effect I am trying to achieve (for reference) and also the hip file. It might seem like a simple solution to someone out there. Please struck me with some knowledge! Thanks!! Color smoke ref.mp4 Color_Smoke.v68.hipnc
  5. Sounds simple but i've never done this before. How can i bake particle positions into a texture sequence? the point count is the same through out the animation their position is always on XZ plane and 0 to 1 space
  6. Hey guys, I have a particles simulation wrapping around a sphere (with min_pos) , I need to prepare a render for Nuke, which has the simulation unwrapped 360 degrees (as HDRI), do you have any idea how to do it? Basically the unwrapped simulation needs to work as a texture in nuke where the compositor will be able to wrap it back to a sphere (an eye of a character).
  7. Hey there! Please anyone help me with this. I have made an effect of Ground Fracture, where the fractured pieces are being cracked and from that Debris particles being generated. Here i made debris from the pop network and then instance fractured pieces on my particles. For the collision of debris particles to the fractured ground, i added static object in the dop network, and make the "deforming geometry" on so that Debris particles should collide in behavior to the Ground fracture performing. But when i set these all setup, then the problem occurs of sliding debris. Please can anyone tell me how to not slide the debris. When i normally added Ground plane then the debris is performing fine, but when i add static object as my Ground fracture with "Deforming geometry" on then Debris particles are sliding. What is the reason behind this? I attached some files or examples for your convenience. Any help will be appreciated. Thanks mate! Debris problem.mp4 Debris problem_v2.mp4
  8. Hey there, I have a simple setup where I generate a bunch of particles and let them drop on some spheres. I would like to achieve to change the Color of the Spheres based on hit by a particle. With hitprim I was abled to change the color of primitives of the spheres but I would like to check based on the selected primitiv to select the whole Object. Also I would like once changed from Black to Red to keep the color even after the particle passed through and left the object. And on top of that, if possible to add some delay. So once the particle hit the object it takes like 10-15 Frames till the spheres changes color best with fading to that color (but not sure if that is possible).. Has anyone an idea how to achieve that or is there a different way. I tried with attribute Transfer but couldn't get it to work. I uploaded my current setup: Particle_hit_detection_changecolor_01.hip
  9. Dear all, Plz give me some suggestions to do simulation of talcum powder as I shown in attached reference gif. Thanks in advance..
  10. Attach pyro sim to insane particle speeds

    Hello I have set up a particle simulation, where the particles are moving with fast speeds.. now as I am rastarize them and bluring the edges, I still get pointy smoke... then I have add some substeps to the smoke sim in the pyro solver node, but still the same result.. does someone knows, how to tackle this problem and get a nice and flowing pyro sim with a fast particle system? Help would be much appreciated
  11. Hey folks I have set up a particle simulation where I have then attached a pyro sim to it (through the rasterize attributes volumes node)... Also I have imported a few objects where the smoke sim should interact with... Everything is fine, until one point: When I am wanting that the pyro sim should collide with the object (seen on the screenshot), then the smoke is just going through the "wall of dirt" (its just a wall with some grass and dirt... ) I just need the collisions so that I can then export the smoke simulation as a vdb sequence... What I have tried so far: - I have give it more thickness with poly extrude node (also added the collision guide thing to look if everything is fine) - also I have increased the substeps on the smoke sim - I have add a object merge node in the pyroFX node (as seen in the screenshot) - just ignore this one node where I have add the red line... But everything I've tried so far, I got no luck to fix it..
  12. Houdini fixed Point Count

    Hi everyone, I am doing Houdini now for over 2 years and I love the software and the community! I recently face a big problem which i cannot solve on my own and cant find anything out there. to understand my problem you need to understand my workflow: since i got a redshift liceense locked with c4d i cannot render inside of houdini :/ so i usually create the simulation inside of Houdini and export it to c4d via alembic to render it there with redshift. (which is allready enough pain) whenever i create a particle simulation which has no constant point count like there are spawning new ones or they are dying somehwere i get really weird results in c4d with the cloner or rs matrix. i copy single polygons to the points in houdini and export it via alembic. In c4d I scatter now custom objects like different stones (stone A, stone B, stone C....) on the polygons and set distribution to polygon center so every single stone gets the same position as its particle. Or in other words: every polygon receives one particular stone. I also activate scaling from source so for example if i use grains with different size the scattered stones in c4d also get the same size and pretty accurate collitions. if now a new particle gets spawned or dies Stone A becomes stones B on the same location. this results in flickering evertime a particles spawns or dies. I also cannot use a random effector to drive the rotation or color of each stone because it changes every frame. I managed to find a workaround: I just keep the particle count the same without spawning or dying particles but i scale them to 0 or 1 but this is no real solution for me. Since i need to create a lager simulation and just pick out a small piece which i then need. So here is my questions: 1. Is this a Houdini Problem or is it a c4d Problem? 2. how can i fix it? 3. if it cant be fixed are there better workarounds? If you need a video or scene file or something from this problem let me know ill upload one but its for a client job and i cannot show too much. hope you understand and thanks in advance!
  13. Houdini.School | Noise

    Houdini.School | Noise My biggest teaching venture yet. Take your Houdini Noise making skills to a new level with my 3 session class coming December 21st, 2021. Overview video about the class can be viewed through this link. https://bit.ly/houdininoise
  14. Smoke simulation driven by particles

    Hey folks, I am messing around with a particle simulation. Now I want to hook up a pyro simulation which will be driven by the particle sim. This is my smoke sim setup from the particles: (it would be awesome if someone knows, how I could set it up so that there will be the typical smoke mushrooms visible during a rocket lift-off). Because I can't figure it out how to make the smoke going outwards and not just sticking to the particle simulation.. I have tried to increasing the turbulence and disturbance in my pyro solver to break up the thing that the smoke is sticking to my particle sim... but this hasn't worked out yet. Help would be much appreciated Thanks!
  15. Generate Collision Data Vellum

    hello! im trying to make 2 objects to collide with Vellum and have a lil bit of squish when they do. i managed to get that part out however, im having troubles trying to get the collision data / impact points. my idea is to emit particles where it hits. any idea how i can do this? please help thanks
  16. Hi, I'm getting some very weird behaviour with some of my particles that collide with my VDB. They should come to rest but a small percentage don't ever stop moving. The collider is a VDB created using the Collision Source node and represents the original RBD pieces converted to a volume. I've tried using Auto Sleep and various other methods but these same particles just never stop. In one of the videos the purple colour is the active particles and the red are the sleeping particles. I've upped the substeps in the pop solver to 20 and they sill move. Any advice would be much appreciated. POPNeverStopsFlipbook.mp4 POPNeverStops.mp4
  17. looking for a tutorial

    I try how to create this simulation https://www.istockphoto.com/it/video/conto-alla-rovescia-per-la-morphing-10-secondi-conto-alla-rovescia-della-sfera-conto-gm1327612600-411918985
  18. I have a 1 object that consists of a ~1000 closed curves/splines (same ammount of primitives), i want to generate particles on each curve and move those particles along them, but each particle stays on that same curve it has been generated onto. i started with popnet with a force and a pop wrangle @P = minpos(1,@P); but of course the particles are jumping on the next spline when it comes near it, which i want to avoid. Also tried adding the popnet inside a for each prim loop, but not sure how to use metadata from that loop inside a popnet (particles disappear after the 1st frame) Can any1 please guide me on what logic i should be using?
  19. wave-like information transfer

    I am building a flock using separation, cohesion, and alignment, but I'm modifying the alignment variable. Research showed that you can use a superfluid equation to define the speed of the turn information traveling through the flock, and that helps give the flock that really fluid look. I'm trying to figure out how to control the speed of the information. I need to 1. be able to dynamically change the speed of the information based on the flocks cohesion (when they're more cohesive, the information travels faster) 2. be able to send out "waves" of information every frame, so 24 times a second 3. send out non-disappating waves (I tried the ripple solver, but one of the problems was the dissipation of the magnitude of the wave) I'm thinking CHOPS might be the best bet, but right now I'm just finding a lot of CHOPS information dealing with sound and audio. LMK if anyone knows of a good node that could help me. Right now I'm looking into just hard-coding it in VEX (basically storing the velocity of ALL of the boids at 10 frame intervals), but that will be VERY intensive.
  20. I have a scene with a lot of particles that I am trying to optimize. I've already culled the particles outside of the camera, but I want to get rid of the ones that aren't seen by the camera's rays (the shape is blobby, so I can't just use the z position). What I'm trying to do is take into account the pscale and delete the particles that are hidden behind others. I have a basic working solution in sops via a for each, but it's painfully slow. I want to try and do this with vex. The end result would need to work on millions of particles. The basic steps I thought of are: 1- find direction to cam 2- ray particles to cam (rayline) 3- find neighbors along the rayline 4- use pscale to determine if this intersects with neighbors' pscale 5- if it intersects multiple times, remove the original point I've attached a file for what I used in sops. If anyone has any ideas on how to make it faster or a way to get it working with vex it would mean the world to me. I assume it would be with the intersect() function, but I'm not very familiar with it. Thanks particle_intersect.hip
  21. Delete Vellum Particles with constraints

    Hey Guys. I was wondering if there is a way to delete particles in a Vellum simulations when they have had constraints? The scenario I have setup the particles have constraints, then I remove the constraints based on a condition, and when I try to remove the particle as well it craps out on me. Attached is a simple example file to showcase the issue.DeleteVellumParticlesWithConstraints.hiplc Thanks
  22. particles disappear after colliding

    Hello guys, I'm trying to build a simulation of blood through a vein. The setup is simple, a vein (tunnel) with particles moving through. They collide with the vein and themselves. I then use this sim to copy objects on the particles. The problem is each time a particle collide, it disappears... And I haven't setup the collision response to die... How could I fix this? Thank you... PS: I want to use different models for the blood so that is why there are several objects. Alain bloodflow_sim_debug_001.hiplc
  23. hi, i want to ask that how i create shape(skull) from a smoke(cigarette smoke) ,i try many things but can not make so can anybody help me regarding this
  24. Surface Advection [Houdini.School]

    Hi all, just wanted to let people know https://www.houdini.school is having a 15% off Labor Dale sale. Use LABOR15 at checkout. Ends September 6th, 2021 PDT, so move quick. The sale includes new classes too. I have a brand new live class coming late September as well called Surface Advection. You can enroll and view a teaser video here: Surface Advection
  25. Houdini Artist

    TOYBOX ANIMATION NZ is looking for remote Senior Houdini artists for an abstract/experimental project. Ideally you would be available to start asap. Please send example of your work and details to:play@toybox.co.nz
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