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Found 637 results

  1. Volume source random activation

    Is possible to have my particles from the volume source activated at different frames? i am using a noise that i remap to frames to control which parts of my geo get activated when
  2. I have two flip sim coming from two different Dop volume source. I am using one fluid object. I would like them to collide but repel each other as if two tongues kissing. How can I achieve that? As always, thanks a lot
  3. Flip invert mask

    Hello guys, i using the Particle Fluid Surface SOP to build the mesh of the simulation, however i need the increase the volume of mesh just at bottom of the model. i find the mask options quite usefull doing that job when i place the geometry to use as mask, the entire simulation mesh gets dilated and where is the geometry still same size (its inverted) i trying to set the dilate thing just inside the mask, but with no luck yet. thanks in advance. ps: i uploaded an basic .hip scene flrip_mesh_masl.hipnc
  4. Hero Waves + Simulation

    Hi there! I'm working on an effect to create a kind of hero / tidal wave look using the regular Ocean Spectrum SOP and a VOP-based deformation. I was trying to find some information online about the various approaches for an effect like this to create some secondary simulated effects for whitewater / splash. There's a couple threads here bouncing the topic around but curious how you would approach an effect like this. Currently I'm taking the output of Ocean Evaluate and deforming it + copy and pasted the same VOP inside the "Ocean Foam" node in the displacement section. As you'd expect, because the velocity of the deformation itself is sort of lost in all of this (and because I don't think the Ocean Foam SOP is meant for this sort of thing) the foam particles just stick to the top of the mesh. I also noticed in my research that in waves like this there is this sort of upward-moving whitewater that creates beautiful streaks in the wave (in addition to the bubbling, foamy cusp of the wave). Ultimately looking to add a collider into the scene and create a sort of "surf" effect but that comes later Really loved these big waves as a reference: I've attached my *pretty basic* .hip file for you to take a peek at! Excited to hear your thoughts! TidalWavePrototype01.hip
  5. FLIP fluid moving around object

    Hello guys i with a job that has an droplet falling into object then embracing/huggind the geometry. i using an POP curve force to guide the fluid along an line however the initial point of the curve is really close to the end point curve, while in simulation it start to stick/attract the particles promptly in the end of the track. i would like the fluid flow completly trought the curve, without it getting stuck at end of line at start. please help ps: im build an simple .hip file to explain flrip_round_object.hip
  6. Hey there! I'm trying to fill a fractured box with water and make the water come out when walls of the box start breaking. The thing is that the collision works when the box hasn't been fractured yet but once one of the walls of the box starts fracturing, the particles start to clip through the box until they completely disappear. The box has thickness, I'm using a deformed static object with a vdb of the rbd fracture. The sim also have sub-steps. I uploaded the hip file, just in case someone wants to take a look at it. Thanks in advance guys! Flip_Collision.hip
  7. Filling water tank

    Hi everyone, I have an issue about filling a water tank - my question is: how I can fill a wave tank emitting particles before? My problem it's when I start the simulation with a water tank all works fine but when I try to fill the same box with a emitter the fluid can`t get the same water line with the same particles amount. Here some screenshots and the hipfile. Thanks! water_fill_001.hiplc
  8. 3D Generalists and Houdini Destruction Specialists

    Hi guys, Come and join us for our new project! We'd love to get in touch with you, especially if you're a well rounded and seasoned 3D Generalist or Houdini destruction ninja with the skills outlined in the flyer below! Vancouver/B.C. area locals only please! You can check out our latest reel here: Cheers, Manu
  9. Hi, I have a problem with my flip bucket fluid sim. I made my bucket really big to not have to deal with to much sub steps.... but it still go through the mesh. Im using volume collision vdb (filled interior) move particles outside of collisions... is there something else I forgot? the bucket isnt going that fast but already gets inside the geometry thnx in advance
  10. Hi. I am crawling from being a Houdini beginner to intermediate and with flip sims I had a few ques: 1. Both geometry and volumes can be used to construct flip simulations. I'm not quite sure when one might chose one over the other and specifically when you might feed a volume into the flip solver. (is the post solve input, the input for the volume?) 2. When building a flip sim i'm a bit confused when you would use the flip source node. You can just use the geometry as the sop path for a flip object in the dop network. So why/when would you use the flip source node? Thanks
  11. Hi, I'm having some trouble getting the 'Vorticity' attribute to show up in my cached sim: I've already made sure to check the 'Keep Attributes' for the fluidcompress node with 'vorticity' previously also checked 'Transfer Attributes' with 'vorticity' Also tried recaching everything again, but it still doesn't show up. Will appreciate any help I can get, thanks!
  12. Hey there, I've encountered imo strange behaviour with my flip Sim. I got Liquid running down stairs. The Liquid should be a bit viscous so I introduced the attribute on SOP Level. For the collider I used volume collisions and a pretty high-res (.002 voxel soze on a 5m Stair) VDB to which I am pointing in my Static Object. When I simulated the liquid with f.e. 100000 viscosity (I tried values from low to super high) its just behaving like water. As soon as I decrease the resolution of my collider it works as expected, or If I increase the resolution of my Flip Sim while leaving the high-res collider as it is it also works as expected. My Question would be: Is there a dependecy between the resolution of the collider and the fluid? does a low res fluid not work properly with a high-res collider? I thought the more resolution on my collider (not too much to keep it efficient) the better. But it seems like that is causing issues -- in my case the solver ignoring the viscosity and the fluid splashing like water while showing correct viscosity values in the GEO Spreadsheet... Thanks in advance and stay safe!
  13. Hi guys, Does anyone know how to achieve this kind of softbody with FLIP viscosity? (pls check the video, it should start at thr right time) anks Th
  14. Hi everyone! I try to create some cool waves in a FLIP tank with another object movement (a basic cube with a subdivide node) When I launch the simulation, a nice wave appears but the liquid level go down but constantly ! Why? I've already tested with substeps of 2 and 3, it's just a little bit better but it isn't the solution, and the calculation increase too much ! Have you some ideas or tips for me ? Many thanks in advance! 006_Waves_test_01.mp4
  15. FLIP Collision with Alembic.

    Hi all, I've been combing the forums trying to get some fluid to stay in this fairly fast moving alembic animation which I think I've converted to proper polygons. I'm wondering how to make the fluid stick with the alembic container (martini glass) while still maintaining some sort of fluidity. As of right now it ghosts through my collision vdb on a faster move. I've tried fiddling with a number of properties like the resolution of the collider VDB / particle scale / particle separation / seeding / attribute transfers , but I fear I've just checked something I shouldn't have somewhere along the way. Excuse my novice ways and feel free to school me on better workflows. Any advice or solutions much appreciated. Thanks in advance. Flip_test.zip
  16. Hi, guys, It's a very simple scene. A torus emit particle fluid into a box . (fig.0) I cached a compressed flip fluid , and retime(speed=0.6) it , the particle fluid surface node will not return a correct result while the "Union Compressed fluid surface" checked. It seems like the compressed fluid surface is not at the correct location and make a very strange result (fig.3). The retimed particle looks ok ,but the mesh not. fig.1 is particle, it's correct , fig.2 is compressed fluid surface, it seems not at the correct location, fig.3 is surface polygon soup. There is a very strange artifact. Is there a way to retime compressed fluid? Thanks!
  17. Im working on a scene where I have some berries falling into milk. The scene is set at slightly larger than real world scale. When the berries fall they are falling at a relatively fast rate. Because of this the dopnet does not have enough substeps to collide the fluid with the mesh (which is a volume collision) and I get a cratering effect like this. I also have the Re-evaluate SOPS to interpolate geometry box checked on. However It does not seem to do anything. The only thing I can do is increase the substeps in the outer dopnet itself, but because of that interpolation, the velocity is less and I do not get as much splashing. I thought it was a scale issue, so I increased the scale to a 5 metre bowl. It still gives the same issue as pictures below. If anyone has any ideas about this issue please let me know. I've been banging my head on this project for three weeks.
  18. Divergence field in FLIP fluids

    Hi, I'm trying to understand how the divergence field works in Houdini, and how it interacts with FLIP fluid particles. Positive divergence should cause the fluid to expand but there seems to be a difference between having positive values in the divergence field and having positive values of divergence in the particles attribute: -If I have positive values of divergence in the particles attribute, the field copies this values (or does some other math operation) and the fluid expands. -If I have positive values of divergence in the field, the particles don't inherit any divergence and the fluid stays the same. -If I disable the option "Divergence by attribute" and have positive values of divergence in the field, the fluid also stays the same. Another thing I can't understand: If I want to fill a volume of 1m^3 using the gasequalizevolume micro-solver with the paramater "Scale Goal Volume" set to 0 then, according to Houdini's Documentation I have to change the parameter "Add Goal Volume" and set it to 1. I tried this and the FLIP solver simply copied the value 1 to the divergence field which doesn't result in any change on the fluid surface. Could some one shed some light on this behaviour, and what is the correct approach to fill specific volumes knowing the total volume value? EDIT: The divergence field is actually working as intended, I was modfying it in the sourcing input rather than in the velocity volume input...
  19. Hi everyone, I have a persistent problem with flip simulations. I have a guided ocean layer sim with a flip surface and a boat sailing (static object in the simulation DOP). The problem being that the inside of the collision boat is filled with particles every frame because of reseeding. I already have "Kill inside collision" checked in the Ocean source node and I don't want to turn off reseeding. Is there anything that can I do to avoid the reseeding inside the collision vdb? Am I missing something in the workflow?
  20. FLIP Simulation

    Could somebody have any idea how to make this kind of sim? fn.mp4
  21. Whitewater SIM issue

    Hello guys, i have a doubt on my whitewater sim.... whitewater01.mp4 i want whitewater to be only on the areas of splashes not on the previous frames rising up... could someone tell me how to make that work?
  22. Hi there! I'm still new to houdini and I'm having a lot of trouble on a project and was wondering if I could have some help or at least some direction on how I could achieve this effect. The project is to simulate a pool of lipstick with a rotating animated object in the center. To resemble the lipstick viscosity I wanted to make a very dense fluid/particle sim, with some clumps of even denser material. Here's the best reference I could find for the effect https://youtu.be/zBGgfPXwLMQ?t=165 . I tried to make a Flip sim with high viscosity and create a viscosity map with a noise sop for those extra viscous chunks, but I couldn't make clumps like I wanted to. I don't even know if the Flip solver is the best tool for the job, but I couldn't think of anything that would get me closer to what I wanted. I also tried to create a few pieces of RBD objects in the middle of the pool, but it didn't work at all. I just really have no idea if I'm on the right direction. I'll add the hip file aswell as a flipbook of the meshed sim. I am using 18.5 by the way. Any help or direction is appreciated. Thank you! lipsticktest.mp4 LipstickPool.hiplc
  23. Hi, The problem is getting RBD Bullet pieces to floating properly: Icebreaker_fake_Buoyancy_Bullet_SpinningProblem.mp4 IceBreaker_Ship_PopForce_VexMask.mp4 im running into problem simulated flat sheets of ice being buoyant in a volume. I can get them to rise to the surface with PopFloatByVolume and also a fake popForce with vex using the pieces depth to mask the upward force. The problem is getting them to not spin around the packed bullet point per piece, and instead have proper per point of the mesh have force applied as per proper buoyancy would. So they lie flat once they get to the surface of the water volume! Struggling with the PopFloatByVolume spin settings, and PopSpinByVolume doesnt seem to play ball either. Im trying to go down the setPrimIntrinsic route, where i could blend slowly the rotation to be flatter as they get to near the surface, but im not hitting gold yet and would be great to know if theres a better route. any ideas or approaches would be amazingly appreciated. attached the hip file with where im at. IceBreaker_PopFloatVol_CustomVolumeInput_005.hiplc
  24. FLIP - Create a Custom Field

    Hey guys, how can I create a custom field on FLIP? I'm trying to achieve this. I guess I could advect the new field using a gas advect but I just can't add this new filed to the sim. Scene file is attached with a small progress Thx Custom_Field_Advection_0101.hiplc