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Found 214 results

  1. Hi; I would like to fill an animated (deforming) geometry, with fluid, and I want the fluid to flow out of gaps shown in the image below. Please take a look at my hip file. I tried several ways without success Thanks for helping. Test2.hip
  2. Hi everyone, it's as the title says. I'm trying to create a basic setup where I have 2 fluids interacting with one another in the same flip sim, then I'd like to separate these pop streams to mesh each separately. I've included my working file. Any help would be greatly appreciated! SeparatePOPStreams.hiplc
  3. * Posted the same question in Houdini forum. But no reply until now. So reposting here I want to create an effect where a Flower is getting hit by drops of rain water. The water drops sticks on the flower and slowly drips down. I need to create the wet map. As well as, the flower should react (bend or disturbed) when the drops fall on it. I am fairly new to houdini. If someone can suggest me a path to achieve this effect, it will be very helpful for my R&D. Please suggest me a brief process from where i can start developing. I am hoping to learn a lot from this project. HERE are SOME REFERENCES
  4. pyro smoke issue

    hi I have a problem with smoke upres sim. it's normal when I cache lowres. but when I use upres to sim. the result is weird. the smoke has been cut into quarter after few frames. don't know if anyone has the same experience. I tried to solve it with change my bounding parameter setting. but nothing going good..... ( maybe the problem not from bounding box, because the bounding range in normal in the viewport. not sure....) the video and pics attached. issue_1.mov
  5. Computational Fluid Dynamics

    Hey guys, im looking to step up my pyro/fluid understanding and study Computational Fluid Dynamics (CFD) since i already got an engineering background. My question, is CFD preferable to learn for computing simulations in houdini? Or maybe another branch of fluid calculations that i know not of? Thanks.
  6. Hi, I'm trying to replicate the vomit tool being talked about in this GDC talk: I'm getting pretty confused by pretty much every step after simming the fluid. Im hoping someone can help me or point me in the right direction to learn about how I would: Convert the fluid into an SDF Write a script that will have every vertex in a grid sample the SDF Use that value to return a colour value Render out the resulting blob each frame aggregate all those frames into one texture that I can step through in engine If anyone can help me with any information to get through those steps I would be hella thankful!
  7. Flip whitewater boundaries

    Is there an easy way that to size my flip container to ensure that my flip sim and whitewater stay within the boundaries? Thanks Josh
  8. Floating Fountain

    A passion project re-using footage shot a few years ago. The water is split into two sims: the first covering the sphere and the downward stream, the other filling the basin and overflowing around the sides. A total of over 7 million particles make up the fluid sim. Software used: Houdini Redshift Nuke
  9. Hi, I am specialized in Houdini FX, Simulations (flip, pyro, RBD Bullet), VEX and Python scripting also a good experience in lighting and compositing. Currently based in Shenzhen, China (willing to relocate worldwide). you can checkout my vimeo for my work and contact me on LinkedIn. Available for freelance/full-time Houdini FX work and Houdini pipeline development. Thanks, Mahesh MS. vimeo: https://vimeo.com/maxcolor/ LinkedIn: https://www.linkedin.com/in/maxcolor/ email: msmahesh@live.com
  10. Thin Sheet Fluid

    Hey everyone, so after my very long thread (https://forums.odforce.net/topic/44053-implement-kernel-maths-in-vex/) I finally found a solution. The setup works great at 0.05 res, you might have to dive inside the solver and change some parameters to get it work at other resolutions (especially to get the droplets). Here are some test : Emission threshold at 60 (depending on the situation, there might be some abusive expansion, like at the end on the rubber toy, but this seems impossible to fix when you want a full thin sheet) Stretch threshold at 0.75 / Surface Tension 0.5 Emission threshold at 15 / Stretch threshold at 1.25 / Surface Tension 1 Houdini default Flip with Surface Tension at 1 Crown test with 50 Emission threshold (problem with infinite expansion with liquid dropping from the collider) If someone has suggestion to improve it, feel free to tell me I'm still working on fixing the infinite expansion issue, but the emission threshold is doing great until 20-30 depending on the situation Cheers, thin_sheet_solver.hipnc
  11. I (beginner in FLIP Fluid) have a FLIP simulation that gets crazy when I add a collision (static object) I use the test geometry shaderball, used 2 spheres with mountain sop, boolean with front and back of the shaderball. The two deformed spheres are the source. The rest (boolean difference) of the shaderball is the collision. Flipbook Without collision https://streamable.com/qkh2p Flipbook With collision https://streamable.com/922a6 Ii feel it has something to do with possible intersection between particles and collision geo, so I reduced the size of the sphere to leave a gap with the collision geo but the flip sim is still going crazy. Any idea? Issue with FLIP simulation.hiplc
  12. Recent work from Chinese animated feature 哪吒 (NeZha), I was responsible for creating and rendering of the water effects using Houdini flip to build a guided system for water and render in Mantra, final compositing done in Nuke.
  13. Fluid into FLIPtank + interact

    What I am trying to do is to get a fluid of any kind (pop or flip presumably) to interact with the fluid in a flat fliptank. Seems like it should be easy, but I can't seem to get them to react and mix like fluids (or interact at all actually). More detail: I actually am trying to get a cloud of blood to spread out into a pool under a body that has just fallen in. Perhaps this means I need a different solution than if I was dumping particles into the tank from an emitter outside of it, but I can't even get that to interact, so any advice on this would be most helpful, and I am grateful to anyone who spares even a moment to consider the problem. Much appreciated! PS- I have scoured the internet, including this site, for advice on this, and have come up empty handed.
  14. If you're flip simulation flickers from using reseeding particles this threads for you. TLDR: I've found a temp solution but want a better one. Inside the flip solver search for a node called "Gas Seed Markers"(Its renamed to "Reseed Particles") Uncheck the "Build Inside Surfels". This will stop the popping but maintain the effect of deleting the unnecessarily dense overlapping particles. Starting this thread for myself to document my thoughts on this but also for anyone else who needs reseeding to keep their simulation in check. So far I have a temporary solution to my issue but I want a better one. My hope is that we can discuss a better means of achieving the desired result of consistent fluid particle density without flicker or popping. The masterclass doesn't explain reseeding and I couldn't find much on the topic in forums or elsewhere for how it works. The node responsible is Gas Seed Markers(GSM form now on). It checks the number of particles per voxel within the surface field for inside the fluid and outside within a given number of boundary voxels and does three things. A. When particles exceed the desired density per voxel GSM will cull the points of that voxel. B. If voxels beneath the surface do not have the correct density GSM will add points. C. If there are not enough particles on the surface, within 2-3 voxels GSM will fill that voxel with the desired number of points per voxel. It seems on one frame the GSM node will delete ALL particles within a voxel that exceeds the limit. Then the next frame, because the void was created it will then repopulate the void with the desired density. So this is where I'm hoping for some help in understanding, in order it's: 1. GSM determines particles are too dense. 2. GSM deletes all particles in voxel. 3. Complete solve (particles partially close in on this void) 4. Next Frame of solver - void still exists so GSM adds particles to this voxel with points = Flicker / Pop. So to start the thread: First - Does Gas Seed Marker delete all particles within a voxel that exceeds the density limit or is this an optical illusion? Second - I'm having trouble getting this node to function outside the context of the flip solver. I want to see it populate points into the Geometry data but it has a lot of requirements regarding the slice index that I don't fully understand. If anyone has or can create a working example of this node functioning outside the context of the flip solver I would greatly appreciate it. For now I'm going to try using two GSM nodes one after the other. The first only performs the cull operation and the second performs the fill before processing the solve. Will post back with results shortly.
  15. 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
  16. create flip tank inside object

    hey there, im newbie to houdini and here. Im trying to achieve fluid in bathtub, easiest way seems like using flip tanks. But i don't know how to do that with custom shape instead of box. Also i will add some rigid bodies top of that water later. Also i tried to fill it with particle emitters but i couldn't success. Also how i freeze it after it fills, initial state ? In short: bathtub with water, floating rubber duck and some other model in surface. attached scene file. bath.hip
  17. (I'm not good at English) I wonder How to I delete the particle from collision boundary. according to the Kill Inside Collision is Delete any particles inside any collision objects plugged into the second input. flattank size equal bounding box group to create .. um.. I need solution and vex sentence. Would you explain this ?!
  18. Simulating flip from bottle

    Hello everyone. Long time since last post here when i was dealing with the same thing. After watching some tutorials and learning some more in houdini i decided it was time to go back and see if i could get some better results. There is still some big questionmarks that im seeking answers for. Here goes. This is the simulation i want to do. Animating a beer bottle (prefferable in maya since i have a rigged character and i have made a animation that matches footage so i know that the animation is timed correctly and so on. The bottle will be pouring beer into a pretty standard glass. When i have a stable flipsim i would want to go on and simulating bubbles and foam. So on to the questions. 1. I have noticed some differences between using collision geometry made in houdini or imported geometry. Making the geometry in houdini seems to work much better for some strange reason. Can anyone confirm this? It seems that i get away with much higher settings on particle separation and gridscale then using similar objects imported from maya. 2. Scale seems very important here. Simulating in real scale gives a lot of trouble. therefor i scaled the bottle up so that it is around 1 meter high. However, this gives some problems when it comes to actually using the animation i made in maya. Everything in maya is done in centimeters and when importing it to houdini its way to big. I ended up matching the animation inside houdini from the imported file and used that instead. Wich is the best way to get around this? Usually in production everything is modeled in correct scale in maya. 3. Setting up the flip source. Is this the correct way? Import the fbx file with the bottle. --> create a new geo node --> create a box big enough to cover the bottle and up to the level where the liquid should end at the bottleneck. Object merge the bottle into this geo and connecting a boolean with subtract b-a settings. Then i blast the exterior so i have only the interior of the box minus the bottle. 4. In the bottle geo i have a transform and after that a null. i put the displayflag on the null and then create a deforming object from that. 5. finally i create a static object from the imported glass. Now all is setup to start simulating. ofcourse there is alot of tweaking of particle separation and collision settings to be done but overall is this a good setup? I can post a file if that helps. Finally some other questions. When caching out the flip to simfiles i only want the particles to be cached. where do i set this up? Regarding substeps, if i raise the substeps INSIDE the dopnet on the flipsolver will this generate more substeps when caching it out or is it only the substes on the dopnode that sets substeps in caches? Sorry for kinda of a long post but if anything can be answered i would be grateful! THX!
  19. Flip Sphere Motions

    Hey there, I'm trying to replicate this setup: Liquid Sphere Based on my scene, I have a sphere and the particles are generated from it with iso offset and particles from volume. Within FLIP, I tried to control the velocity with pop forces (POP force, pop attractor and pop axis force) and got somewhat of a swirly motion but the in the reference video, towards the end you can see the fluid is ground around a torus like motion and the shape as well Any pointers on achieving this? HIP file attached included. Thanks! SH02_Water_v02.hip
  20. Hi, I have an issue that I have not been able to figure out. I need particles/fluid to follow a curve, which I know how to do easily, but this particular curve crosses over itself a couple times so using Volume Velocity and Curve Force causes to particles to divert off by grabbing on to a later section of the curve. (ref images attached) Is there a way to restrict them to the current section they are on so that they ignore the areas where the curve crosses over itself? I have not been able to figure out a way to do it so I thought maybe the amazing Houdini brains on here might have an idea? Thank you in advance for any help/suggestions you can offer!
  21. Hi there everyone. I am having a really strange issue with my river scene when I render it out. The reflective of the water seems to turn on and off randomly. I then did some further testing and found it to be the interior Volume giving me issues but this only happens in the center section of my River, the Top and bottom are not affected by this problem. Below I have two Images to show the result of the Volume issue which is consistante on these two Frames even if I re-cache the Sim Frame 350, the Volume in the center is really Thin. Frame 357, the volume is much Thicker in the center. Please check out the Link HERE for a low quality render with a few frames on Vimeo. Password : JodysFX I feel like there is a setting I am not turning on or a value thats two low. It might be in the Surfacing node but I am not sure, I will continue to test. Any help is greatly appreciated.
  22. I have a fluid container from which the fluid has to be sucked out through a straw ? even a small hint would help. pls help././.
  23. Hi, I'm currently working on a project where I'm trying to bake a displacement map and normal map for a number of different waves. I have a method for baking the waves, which have been created in Maya and imported as an FBX, but want to get extra detail on the wave surface. I managed to get the ocean spectrum to use the animated wave, but the problem is that the bake needs to tile and the displacement of the ocean spectrum doesn't. I'm having trouble figuring out how, or even if its possible to create a fluid simulation that can use the wave animation. Thanks in advance.
  24. Bullet to Fluid and Vellum

    Hello Everyone, I have just create tutorial of making dynamic to fluid and vellum in Houdini 17. Check in here: https://www.cgcircuit.com/tutorial/bullet-to-fluid-and-vellum Best Regards,
  25. 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
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