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Found 479 results

  1. How would one increase FLIP viscosity based on particle age, to get a thickening/coagulating effect? My searching only found one how-to from 2012, which doesn't work in H17+. I understand setting viscosity by attribute, but it appears FLIP particles don't have an age attribute, so I'm not sure how to shoehorn one in there. Thanks!
  2. Hero Object rest force in flip

    Hi everyone, I got a flip sim with a hero object Floating on top of it. Now I want to make sure, the object floats but kinda stays on a specific spot. So I used the rest Attribute and subtracted to Position from it (in the dop net). If the distance is getting bigger the force should increase as well. Unfortunately the force is pulling the object to the Center of the Scene. Maybe any quick solution for that? Added a supe rsimple hip file heroforce.hiplc
  3. Hi, I'm struggling with an issue I have at the moment where I have a boat that floats along an ocean surface which follows a curve. The idea is to have a path and an ocean I can evaluate and have a boat bob to the waves (I've done this part) and have a guided ocean simulation follow along with the boat. I've then taken the normal and the up vector and used trigonometry, one unit length circle and vex to create Y rotational data. Then by diving into the ocean source node and applying this to ocean evaluate and boundaries with out interfioring with the ocean spectrum I end up with a rectangular particle source that rotates with the boat allowing me to have a smaller source of particles (instead of a large square centred on the boat) that highlight the back and side of the water next to the boat. My problem from here is the flip fluid solver only takes the centre and size from the ocean source, held inside gas resize fluid dynamic nodes of the flip solver. This gives my fluid simulation an incorrect result. I'd like to be able to apply the rotational values to the flipsolver using position, object position, motion node or anything else that would work. However upon facing this problem I've realised my knowledge in dops is extremely lacking and I'm confronted with green and purple outputs of nodes that don't like working together. I have a feeling this is possible due gas resize nodes ability to rotate for clustering and other pyro Sims, I just have no idea how. Can post my hip when I'm back from work later today, if you have any questions please ask.
  4. FLIP colliders flickering

    So after a very lengthy FLIP sim I'm finding that my colliders are arbitrarily flickering in and out and disappearing altogether. I had done various tests--this happened a lot with lower res settings but seemed to stabilize at the final sim resolution--until frame 240 (of 250). The problem appears to be in the static object itself creating the collision geo. It's set to use volume collisions, mode is volume sample, division method by size at 0.005 division size. The object is an animated person at scale (about two units = 2 meters tall), this setting was about as large as I could go and not lose details. The .abc itself is imported and unpacked. The same object is used elsewhere to drive a pyro sim and it's working fine there. How can I ensure that my colliders don't just disappear?
  5. FLIP Divergence

    Hey guys, I'm trying to use divergence with flip but things get kinda unstable. I'm using only the point attribute, should I use a volume field as well somehow? Thx FLIP_Divergence_v0100.hip
  6. I have a FLIP tank with some action going on. It's just someone diving, so the part of the tank that requires a lot of computation is small, but it's an underwater camera, so with a small tank you see the edges of the simulation. Is there a way to either focus the simmable area in a tank/make particle separation dramatically smaller in one area, to accommodate a huge tank with not much going on so the render times aren't crippling? I've seen tutorials on using lo-res sims to drive hi-res, but that is sort of the opposite of what I'm looking for. I've also seen some endless ocean tuts, but since what I need is an underwater dive, and the breaking of the surface (and the water still beforehand), I haven't found a way to make that work. Thanks for any help!
  7. Whitewater h17.5 Not to emit bubbles

    Hello, Using Houdini 17.5 to create boat wake with white water. Using the white water solver I where I would like to emit foam and spray over the flip surface. However, I do not want the bubbles as I am under the impression this would reduce simulation time and memory consumption. That said, I couldn't figure out a way to stop the solver from emitting bubbles! Anyone was able to deal with this or any documentation or thread that could help?
  8. Freeze Flip Sim

    Hey Guys, Imagine an object which fills with liquid over time. When the object is full of liquid i want the motion of the Flip Fluid stop oder decrease over time. For example: - Object fills with Flip Fluid from Frame 1 to Frame 96. - Liquid and all motion of it slows down from Frame 96 to Frame 144, at Frame 144 everything is not moving anymore. I tried some pop wrangle inside my DOP but i cant get this working. Any suggestions? Should i do this after the DOP in SOP Level in a Vop/Wrangle or could I achive this inside my DOP? And How? Thanks and Greets, me
  9. Hi! I have what is probably a dumb/obvious question. I have a character diving into a pool. He is modeled to scale (roughly two units high), but to get the details of a human diving I'm having to make the collision separation and particle separation very small. The problem is that this is a huge body of water, and the camera is underwater, so the tank can't be isolated to the area of activity or the "walls" of the liquid show. I don't need detailed animation/simulation outside of the area around the diver, just some turbulence to make things interesting. Is there a way I could focus particle density around the area where I need the detail? Can I nest one sim inside another? (The places I've seen one sim driving another have seemed to focus on up-res-ing, and it doesn't seem to fit what I'm doing here.) Or do I just deal with the fact that a large body of water, even if there is not much happening, requires a ton of sim-time? Thank you for your help!
  10. 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!
  11. Good afternoon guys, I'm trying to create a setup similar to the one below. Where the drops are with dynamics and glued to the surface. Does anyone have any tips on how to start this game?
  12. Hey guys, I'm having some issues with a FLIP collision, seems my VDB collider boundaries are affecting the sim, anyone knows what can be causing this? I'm using static object + static solver with a proxy volume as collider. Thanks!
  13. OceanVortex question

    I'm trying to simulate WaterVoltex with Houdini. This is a tutorial on sidefx that is not ours but a credible site. I do not understand, so I ask here. I have set up like a video but the results are not the same. Heap files and video links, I'll leave time Thank you for your help. The reason for this simulation is to create a water simulation using the ship. I will attach a reference video on this If you have any other approach, welcome any way. I will show my enthusiasm to learn Houdini. Thank you for your interest. Plz.. Related Videos Link (19:21 ~ 25:49) Reference Video (4:21 ~ end) voltextest.zip
  14. FLIP - pprevious attribute - What is it?

    At first I thought it was the previous position of the particle but it looks like its the exact same position. Does anyone can explain this? Thanks
  15. Disable (some) FLIP Particles

    Hey guys, Is there a simple way to disable some particles from the simulation like i'd do with RBD? I have a set of particles inside a group and I need them to be stopped at same position but still interacting with the other particles. Does it makes sense? The group is animated I tried setting v=0 but it doesnt work as expected. I did another trick inside a sop solver to get the position from the previews frame so it stays static but then I cant use the resample. Im just wondering if theres a a simple way like like an attribute the would make them sleep. Cheers, Alvaro
  16. Flip Fracture RBD

    Hey guys, im doing a similar effect to the video in question. Not as violent as this, ive done a lot of flip sims but never something where the flip sim pushes an rbd object. The effect im after is like liquid chocolate pushing out from under chocolate that cracks. Any help would be appreciated D
  17. Hello! I'm trying to make an effect where a logo emerges from a tank with a viscous fluid. I want to have the liquid quickly flow off the logo once it emerged. It has a round surface, similar to the torus I exchanged it for in the hip-file I attached. I'm aware of viscous fluid's stickiness and turned on "slip on collision" and also tried the "gas stick on collision" cheat I found in some older thread, as well as using normals to drive the velocity. however some particles always stay on top of the surface and won't flow off. What would be a smart way to cheat and clear the surface of the fluid? Thanks in advance! J. 190620_Instagram_FlipTankExample.hiplc
  18. Greetings. I am the filthiest of noobs and i found a problem i havent been able to solve. I made a very beautiful flip fluid simulation in which two liquid sources mix together. (lots of tuts out there so it wasnt hard for me to do it)...... Both sources have different color attributes and density attributes and they mix flawlessly..... I was successfuly able to do the simulation YAAY!. The problem comes when our pipeline DEMANDS to render in Maya Arnold........ I export the VDB poligon soup via a Rop alembic output node...... and create an alembic file (it exports, it imports into Maya, no problem) BUT..... when i have it in Maya, I havent found a way to mask the fluids, so an AI mix shader lets me use two AI shaders as the two liquids and lets me mix them as they were in Houdini....... I understand there are "Weight attributes" that come with the alembic and they should be the ones helping me mask the fluids, but i really dont know how to do it...... Im a noob both in Houdini and in Maya. If anyone could help me showing me the workaround , i would deeply appreciate it.
  19. Vellum FLIP interaction

    Hey everyone, do you guys know a way of making flip and vellum cloth interact with each other? So not with Pop fluid but flip.
  20. Hello! First time posting. I'm new to Houdini, this is my first project that I decided to do. But I'm a fairly seasoned C4D 3D generalist so I know what I want to do in Houdini, I just don't know how to go about it. I'm in Houdini 17.5. Here is the problem. I have stumbled around in Houdini and made a Viscous Flip Fluid Sim. I made a Sphere an emitter, and emitted my fluid pouring onto a .OBJ mesh that I imported in. I've cached the particle FLIP Particle simin the DOP network, the Particle Fluid Compressed Cached, and Particle Fluid Surface Cached. Now here is my problem. I exported my meshed sim as an alembic from a ROP_Alembic node. Imported into C4D. And then I realized I have a UV problem. This is a Redshift texture and shading pass that I did with my sequence. At the time I forgot to plug in the velocity data tags from the Alembic sequence into the Redshift motion vector blur, so if it looks weird, that is why. Crystal_Goo_Test.mov My texture smudges are on the mesh, but they stay static while the mesh animates. It looks just like the textures from this cartoon it doesn't move with it. So after a bit of digging I realize I don't even have UV's. Because Flip Fluids don't come with UV's, and if I never defined any UV's then how could they just magically appear? lol. So I tried researching how to generate them, and how to export them with the alembic. But for my specific situation I couldn't find anything that was up to date and worked. OR I am too much of a noob to implement what I saw in forum posts. The stuff I saw was for Houdini version 13, 14.5 and 16. I'm on 17.5. Here is a screen shot of how I tried to generate UV's and export them, again I never re-cached my sim yet. I just tried to put uv's on my existing set up. Below is my emitter. And there are no UV's on this sphere primitive, nor anywhere before the output. I took a shot in the dark and tried to see if I could generate them after all my caches (because it took 3 days to cache the fluid surface mesh). So I honestly have no idea where to generate these uv's, how to do it correctly, and how to get them passed onto the fluid mesh for alembic export and texturing in C4D Redshift. I'm including my .hip file with my cache's disconnected. They are over 200 GB's all together so it's too big to include here. Lower the substeps in the Flip Solver or lessen the Fluid Mesher to make it play back faster. I used high settings for my final export (also I tried my best to optimize, but again I'm a noob with Houdini and have probably done things incorrectly in my set up). Crystal_Viscous_Sim.zip The FLIP DOP cache might still need to be disconnected. This is the final step of my personal project. I've done all this on my own but I'm super stuck on this UV generation and export. And once I can export this fluid mesh an an alembic sequence for C4D Redshift I will be set to render. Thank you in advance for any feedback and/or answers. Please write out instructions very clearly for me to replicate if you don't want to provide pictures/ screenshots or .hip files. Again what I'm trying to do is generate UV's for my Fluid Surface, and have then be able to be exported via an Alembic sequence for texturing and rendering in Redshift.
  21. Houdini Flip SIMM on a custom wave mesh

    Howdy there!! Poet here. I have a mesh that is deforming like a big Tsunami wave with a boat on top.The mesh is made with Ocean Wave Deformer in Houdini with a Ocean Spectrum on top of it. It's a moving mesh with the curves translated that are connected to Ocean Waves SOP. Im not able to get a proper FLIP simm out of it. The velocity kinda goes NUTS. Also it was difficult in the beginning for me to get the shape right from the Ocean Wave to the Flip Tank Initial it would not take the full deformation. Then I fixed it by going in the Flip Tank SOP and adding changes manually. But the Flip issue is still happening. Anybody or anyone if have done something like that I would be very grateful if you could give some tips. On that same Ocean Wave Foam is also done and looks pretty good. IMP: It's a production file so I cant upload it.
  22. Tips for Eye Candy Fluid sims

    Hello there good people, Do you guys have any tips on creating eye candy fluid sims, Specially Flip liquid Sims? Thanks in advance.
  23. I'm in the middle of creating Whitewater particles for my waterfall sim and after caching out the particles and converting it into a volume it looks extremely low res considering there is over 300,000 particles and 8 million Voxels. Not sure what i'm missing but any help would be greatly appreciated. Thanks in advanced.
  24. Digital asset download at Orbolt! Enjoy https://www.orbolt.com/asset/RodTD::Rod_vdb_averaging
  25. Recreating an ultracentrifuge

    I'm trying to recreate an ultracentrifuge that seperates high density particles from low density particles. My current setup is two fluids with separate densities being emitted side by side to fill the container. Then once the container is fully filled I start up the "centrifuge", a pop axis force to spin everything at high speeds. The problem is it just acts as a blender and not a separator. I have a little divergence to pump up the fluid in the beginning but then it's removed. The densities are about 400 kg/m3 apart. I've tested fast and slower with different drags and settings but still just blends. Anyone else try something like this? Maybe I'm missing something important (more than likely, ha). Thanks! Update: kind of working now adding some mass, drag, and applying the rotation only to the low density particles. Faking it till it makes it I guess.
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