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Found 104 results

  1. Poisson Disk Sampling Help

    Hi guys and girls, I have this condensation on bottle shot I'm working and would love to create a poisson disk distribution with a uniform sample of points based on the area of the triangles in the mesh. I've been looking at the papers written about this but its a liittle bit technical for me at this time. I'm hoping some could maybe look at my file and point me in the right direction to use vex to create this algorithm. Thanks much in advance. poisson_on_bottle_setup.hip
  2. Hello! I've been using Houdini as a TD for about 2 years now and I just recently got my hands on a C4D and X-Particles license. Playing around with X-Particles it has become apparent that Houdini can make something fairly simple (like particle simulations with constraints) very difficult. For these past 2 years I've been trying to get, specifically, thick liquid like particle constraints (not just viscous but stringy) working in Houdini and I've never been able to get results I can be completely happy with. I've been able to achieve "sticky" effects using vellum grains and vdb meshing before as seen here, however, I was always after a different effect using a particle simulation that was NOT attached to a mesh but still behaved in a similar "sticky" fashion when coming in contact with colliders. After trying this over and over again in Houdini and having unsatisfactory results, I've now experimented with X-Particles and I was a slightly frustrated by all of the time I had spent in Houdini and how simple and quick it was to achieve exactly the effect I wanted in X-Particles. In the video below you can see what effect I was after in XP. I was curious if anyone at all has re-created this stringy liquid effect in Houdini with POPs? It seems clear to me that FLIP fluids are not really the answer for small scale simulations where you want a "stringy" surface tension look. I've gotten close with FLIP and vdb meshing in Houdini, but it never looks as natural and real as X-Particles. I've heard that maybe the POP Fluid node may be the answer (here), but I'm curious if anyone has attempted these stringy constraints in a Houdini project! Any Houdini workflow tips for such an effect would be appreciated because the cost of X-Particles and C4D is not something I plan on paying for the rest of my days!
  3. Hi everyone, I have a plant (leaf and stem) merged as one piece of geo with some dynamic animation. I'd like to animate the leaf separately and still be able to keep the current animation. Is there anyway you guys can think of that I could do this in a procedural way? any suggestions would be much appreciated. Even if you have suggestion on how I could do it differently from scratch that would be appreciated too. See attached file. Thanks in advance. philodendron_model_03_for_forum.hip
  4. I've been working on trying to solve a problem that probably has several ways to attack it... but I can't seem to figure this out. I'm trying to have an animated object that rocks back and forth, and inside of that object is a hinge constraint that ideally would follow the object and let the gravity node do its thing. I the example file, Imagine a sailboat on the seas, rocking back and forth on the waves, and the boom rocks swings based on the boat's motion. I've attached a hip file to show my train of thought. Any help is appreciated. hinge_test.hiplc
  5. Stormborn Studios First Reel

    Hi guys, Happy to share this with you! Let me know what you think! Cheers, Manu
  6. Vellum Frame

    Hey all, I need help with something I think should be relatively easy but cannot figure it out. I want to drop a picture frame in with strings attached using vellum. I have set up the wires but cannot figure out the correct approach to attach to the frame. I have a attached the beginning of my set up maybe someone can help me out or give me some advice! Thanks! vellum_frame_jl_01.hiplc
  7. Donuts & Cupcakes! What? This is the theme of my new 3D animation [V2] of dominoes falling down! The goal? Have fun and training my skills in 3D simulations under Houdini v18! Technical details : - Houdini 18 -> Modeling, textures of Cupcakes and Donuts, rigid body dynamics simulations, placement and cameras paths. - Blender 2.83.1 -> Textures, lights and rendering with Cycles, because Houdini's mantra is really too slow to calculate ... Now enjoy it and leave me likes and comments, it's always a pleasure !! Here : https://www.youtube.com/watch?v=0sFKkirxTbk
  8. Cloth DOPs

    Hi. I was digging in SideFX DOPs documentation and noticed such nodes as Cloth Mass Properties, Cloth Material, Cloth Material Behavior, Cloth Plasticity Properties and other cloth related nodes that seem to be missing in Houdini 18. Are they legacy nodes I don't have to care about or have I misunderstood something?
  9. RBD Spheres fall through box

    Hey people of the internet, I feel like I'm being really dumb and I cant work this out. I haven't had much experience with RBD solvers because I usually use C4D for these sort of simple setups. Basically I have a load of spheres inside a box and I want the box to contain them. Unfortunately, the spheres just pass through. I have fiddled with it and can get it to work. If it's set to bullet it sticks some of the spheres and the rest pass through. I have attached a screenshot of my set up.
  10. Hello everyone, I've stumbled upon a problem. What I need to do is simulate thousends (15-30k) individual rice corns. To make it harder, everything should be about real life scale. I've got a setup that emits packed rbd objects, but it gets slow very quickly. What I would like to do is, to set the bullet objects to sleep after they lived for a few frames. The settings for automatic sleeping won't give me the desired result. Adding a Attribute wrangle into the SOP Solver (as I've seen in other setups) disables all rbd objects instead of those that lived more than 5 frames. Any help would be appreciated. I've attached the file where I'm testing this in a crude way. Thank you all! Rice.hiplc
  11. Hey guys! I'm struggling a bit with a setup that's probably quite simple but I couldn't get behind it for a couple of days now. My shot requires me to have pieces which a character consists of (Megascan-assets scattered on a character) follow the character's animation. This looks something like this: walkcycle_fox.mp4 Now what I've tried to far was to go about the following with some fancy orientation math in a SOP-Solver in the dopnet to get the euler-W-acceleration to target the goal-orientation, but somehow the pivot offsets made this way harder than expected. My next approach (which I should have rolled with from the beginning) are constraints. So I'll try to have a soft constraint for each piece to a world anchor and target the rotation. But just how exactly does rotation-constraining work with the RBD-tools? I've found very little information on this topic - only for things that are individual objects, but not 800 pieces... I'm happy for any hint towrads a solution. Cheers, Martin
  12. Hi Guys. This my first post!!! I have been working on a scene where some particles emitted from a POPsop, scaling inside a DOPsop, colliding with each other and fill a container. I have seen this dynamic in a lot of videos, but I never be able to do that (below an example) I think I'm very close to do that, but I don't know is the right way. I did it with the multisolver in the dop network. I attach my project in the post. I did'nt find any tutorial or forum that explain that. Someone can help me please? There is also a trick to stop emission when the volume is almost fill? Thank you. Luther Fill_Object_With_PP_002.hiplc
  13. I'm looking to find a way to make a FLIP fluid sim move particles, which would themselves be used to instance underwater particulate matter or bubbles. All of my Googling turns up ways to make POPs influence FLIPs, but I'm unable to find this, and I'm sure it's depressingly easy. The scene is a pre-animated character diving into water. To get the bubbles as he dives it looks like the best bet will be to emit particles with instanced geo bubbles (correct? No matter how splashy I make the sim, I'm not getting any bubbles happening from the dive itself). Thanks for any help!
  14. Hello, I'm just getting into vellum and the solver seems fast and cool but I'm trying a sim here where the geometry tries to attach to its collision geo, but that ends up being very jittery at the end with what seems to be no loss of energy. I've uploaded a scene file. I've tried to set @v to zero at the end and that still hasn't worked. What're the steps to making this solver behave? vellum_basics__jitter_02.hip
  15. RBD's and SOP Solver

    Hi peeps, I'm using the SOP solver DOP to change my geometry overtime from one sphere to multiple spheres, however, when the geometry changes to multiple spheres it's still behaving like just one object instead of individual spheres and I can't figure out why! Any help would be much appreciated and I've attached the troublesome scene file. Also, I used the RBD Fracture object for this instead of the RBD packed, because I couldn't get the results out of the SOP solver to work with RBD packed object. I unpacked the geo in the SOP solver and repacked the output with the name attribute and it wouldn't work, so also, if anyone could shed some light on that as well it would be much appreciated. Thanks. RBDs_SOP_solver_testing_01.hip
  16. Hi, I was just trying to replace my pieces with hi quality instancing but it gives different geometry in Rigid body Simulation? Could you please guide me where did I miss MANY THANKS PREM wall rbd sim v7.hipnc
  17. Breaking constraints

    Hello guys I'm doing some testing on breaking constraints, for now, I was only breaking constraints based on angle, force, torque and using a slider for adjusting values. Do you guys have any techniques to share for breaking constraints, what kind of rules can be used?
  18. How does Cache in sim works?

    Hi all, I've been doing some FX set ups with pyro and flips and I was wandering if anybody could explain me how not caching the simulations can affect said simulation. let's say that I have a whole set up where I bake the sims after compressing the volumes and simulating, and I want to sim Fire, Smoke, dust, etc on several layers. if I make a ROP network and save to disk from there, does not caching implies it has to resimulate all each time it has to simulate a frame? (I imagine not, but where does it store it then?), let's say I save all the files in the background, this way Houdini assigns a job without waiting for another to finish, If a job gets temporarily suspended, does it has to start from the first frame when it gets resumed, if not, where is the necesary information to resume stored?, is it on the saved .bgeo?, or maybe there is a specific workflow that is already stablished. any light shed into this would be greatly appreciated.
  19. Orient / Lookat for Bullet Objects?

    Hi, I'm hoping someone can help me as I've spent too long on trying to work this out by myself now. I'm doing a simulation with balloons and want to have them start in randomised orientation and then slowly resolve their orientation to have the wider bit at the top. This seems to be possible with POP spin for particles, but I can't work out how to do it with bullet. So far, I've tried altering the orientation manually in a wrangle in dops and trying to find a way of getting a vector into dops, such as with normals, to then be able to compare to an up vector and add in angular velocity until they match. Altering the orient attribute in DOPs seemed to do nothing if you target it directly, so perhaps it needs to be worked on the intrinsics?? Nothing I tried seemed to work, so I'd love to know if there's a way of achieving this, so would be grateful for any help. Many thanks! Toby
  20. Hi, I'm quite new to Houdini so, I'm probably doing something really wrong. When ever I go into my Dop network for my sim everything freezes up and it takes several minutes for any change to update, it's nearly impossible to work with. I've attached my scene File Thanks a lot Josh ImageBased_Destruction_Cobble_Test_002 .hipnc
  21. This is a bit fx, a bit modeling, a bit rendering, so I'm throwing it here-- I am running sims on a tree model. The original tree was too hi-res to simulate, so I had to run Clean and Remesh to reduce its poly count a little bit. It still proved too oddly-modeled to run a point deform on the original based on the sim, but the sim'd model is still high-poly enough so we're going to use it as the final. What I need to do is transfer the UVs, in world space, from the original model to the down-res'd sim'd model. I tried using Maya's Transfer Attributes, which does exactly what I need, but choked on the source model's size. How can I do this in Houdini? (I know there will be some changes, but those should be mostly in the little tiny branches that are okay to lose, and this is not a hero tree.) I assume it will be something like storing the original models' point positions and then somehow applying those points to the end result of the sim'd/cached model, at which point I could do a straight attribute transfer (and although I get this theory I don't know the steps required), or is there a better way (and if not, how would I do my suggested way)? Thanks so much!
  22. **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!
  23. Can't select points in DOPnet

    I have a question that is so dumb that I can't find an answer in Google. I'm working with FEM objects. I need to select points in the DOPnet to make constraints. I can't select points, just objects. Thus: can't do pinning and stick things to things. I've done this a million times on my home computer, but I'm using a different one now (with H17 installed mere days ago), so I'm sure it's some big obvious setting. Thanks and duh.
  24. Radial force for FEM objects?

    So I'm sure this is a stupid, way-newbie question: I am working with various FEM elements. What I need is a radially-orienting force to "push" the objects. However, I want it to pulse, like a fan being turned on and off. (I couldn't get the fan force's shape to behave in such a way to make it completely spherically radial.) From my Googling, it looks like magnet force is the way to work, but it seems impossible to control. I've been scaling a metaball using a sine-wave based CHOPnet, but the metaball itself pulsing on a SOP level doesn't seem to impact the force's scale in a not-unruly way, and the force scale can (seemingly) only be keyed in steps (which is why I went for scaling a meatball). This step keyframing is a problem because I want the force to oscillate to negative values, too, for push and pull. There doesn't seem to be a way to scale it in general within a certain area--i.e. to have a super-strong force the field as a whole has to be enlarged, so one-half of a FEM object can't get pulled on very strongly while the "outside" half is unaffected. I'm used to working with Maya, so really all I want is a nice, tidy Radial field, which can suck and blow (radially) as I tell it. Any help is profoundly appreciated.
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