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Found 228 results

  1. FLIP - Spreading Bloodstain

    Hi, I'm working on a bloostain, that shall diffuse/expand over 450 frames to fill up the whole frame in the end (to be used as a kind of 2d transition effect later on) I was able to do a nifty flip sim, but in the end it wasn't behaving like blood at all. To get more of that blood-like rolling diffusion effect, I tried to introduce some viscosity. But with viscosity on, the stain isn't moving anymore. (The bloodstain should already be there, so no dripping & dropping, only expansion in x and z) Tried different viscosity-values, played around with friction and vel as well, still no luck. I think some viscosity could help here, so can someone point the right direction to get it to work? I`ll attach my tries thanks in advance Houdini-Bloodstain.zip
  2. Hi! I'm pretty new to houdini's flip fluids and I'm stuck with something. I have a flip fluid liquid simulation with boundary layer for river like effect. I've setup a boundary velocity field to create the river flow. Now that I'm trying to add some pop wind in order to add turbulences, it appears that it overrides the boundary velocity effect. SoI'm looking for a way to blend those two effects. Any ideas ? Thanks.
  3. FLIP FLUID Mesh penetrates surface

    Hello Everyone, Particles falling into the object. the particles are penetrating. I've literally tried every single suggestion on every forum and I'm still stuck with this problem. Please look into this. Things I've tried: 1. Substeps increase 2. slip-on collision 3. collision guide offset and divisions. Still, this problem exists. Can anyone help https://i.redd.it/3ziqxtmeo2l51.png
  4. Independent surface tension

    I am trying to achieve the effect of having a solid piece of geometry sitting as a fluid, being brought in by either volume source of pop source. This initial piece just has fluid ripples. The second part is I have emitters in the same dop network that are there to create a dripping effect. So it looks like this liquid that is holding shape is dripping. The problem is that I cant seem to create independent surface tension for the two separate sources. If I increase the surface tension to what I need then the main piece of geometry gets washed out. I have been looking for a solution to this but nothing comes up for Houdini 18
  5. Fliptank fatal error

    Hi ! I am a beginner. Houdini crash when I try to work with fluids. I just created a flat tank, and just to look at the differents nodes, I cliked on the node fluid_compress1 in the fliptank_fluid and a get the "1460: Fatal error: Segmentation fault Saving application data to C:/Temp/houdini_temp/crash.splashdown_01.alice_1460.hipnc" The last time the fatal error occured when I changed the particules separation to set 3. Before I had other fatal errors in differents operations but always with fluids. A friend built my computer recently, maybe there is something wrong with it. I didn't have any problem like this with bellowy smoke tutorial or procedural ground before. Could you help me please ? I have attached my computer config. Thank you !
  6. A small fluid-related question

    Hi, Currently, I'm working on a small sim where a character gradually fills up with water. I'm trying to have more control over the emission rate, when using the emit particle fluid shelf tool. It seems like the "Scale Source Volume" slider on the Volume Source DOP has been removed. Normally, it would be found below the "Activation" slider. I attached a screenshot of the parameter view of said node. So, my question is as follows: where can I find a similar parameter in Houdini 18? Best regards
  7. Fluid coupling

  8. Gas Damp Micorsolver broken?

    I'm using a Gas Damp Microsolver to slow down my pyro sim. However, it seems like it is broken (H17.5.258). No matter which parameter I change, it sucks out all momentum of the sim, bringing it to a standstill. I'm using really ridiculous values, like a Target Speed of 500 (my sim is waaaay slower than that.) As far as I understand it, values below 500 should be ignored, but no matter what I put in there as a target speed, all velocities are lost after a few frames. Scale...well, if it's 1, 0.1, 0.0001 or whatever...it kills all motion after a few frames. Controlling it by a field...same result. Did anybody else ever have a similar issue with this particular microsolver?
  9. Choice between Ripple Solver or full Flip Sim

    Hello, I need to produce fluid animation to get close to this reference picture: The left side should be a very soft wave hitting and bouncing on the bottle, the right side should be a bit more agitated water but still very smooth in general. My dilemma is that i'm hesitating between "faking it" and using a mix of ripple solver and other "non-sim" ways to deform a mesh, or to go for full on flip sim. From what i tried already, and what i read, having very calm/subtle flip sim is not easy to achieve at all, so i was thinking for now that the first "faking" solution would be more appropriate. I would be very interested to know how you would approach this situation. As an example, this is what i'm getting for now for the left side with a simple ripple solver and some caustics. The caustics helps a lot to make the render interesting but the movement of the ripple is a bit boring for now.
  10. Was experimenting with the fluid sims and I had an idea to make the fluid affect the object as if it was a paint for e.g. if we threw a red paint bucket on the wall it will leave stains behind.
  11. Hello Everyone I am mixing fluid colors in a pretty simple small scale flip simulation. To that point things behave as expected. This is the problem that I encounter: I set the desired color to my emitter (let's say it is required to match an existing product), the Cd attribute is then transferred between neighboring particles throughout the solve. Ok there. The problem is that, as the colored fluid dilutes inside the clear liquid, the colored fluid then darkens unacceptably and the two never really blend into each other (I believe in real world, the darker color would remain the same or lighten as it dilutes into a clear liquid, depending on the viscosity). This is partly due to the 'at distance' control of the 'transparency color' but in my case I can only set it correctly to either the stream (thin) or to the contained fluid (deep) but not both. Also I am not yet capable to build shaders among other advanced techniques. I would need the color to match a rose pink troughout the simulation. Is anyone able to manipulate some attributes upstream or knows how to render this correctly. Many thanks V Here is a simplified Hip sim easier to move around https://www.dropbox.com/sh/26nzu9mve1ztcmb/AAD3mw4w1hX9O1sXpgeGaDLZa?dl=0
  12. Hi all, new to the forums and new to Houdini although I have a long history in Maya, I have never really gotten much into simulation until now. I've been messing around with the shelf beach tank to make a simulation of waves for a project I'm working on, but I'm a bit stuck on the caching phase. Currently I have a file cache for my fluidcompress and then one for after my particlefluidsurface that then goes to render. Everything seemed to be okay, but I wasn't really able to scrub the timeline without long cook times seeming to come from the Import DOP I/O node. Rendering with Renderman also would get stuck on generating scene. I saw that you can save to disk right in the DOP I/O, but I'm going with a final particle separation of about 0.07, ending up in 6 hour cache times and 100+ GB for 150 frames. I'm guessing this is normal? My machine is 32 GB RAM with a Ryzen 7 2700X CPU. Just don't want to waste time and space on something that was not the best solution. I am left wondering if instead of the DOP I/O node I should be using a filecache after the delete_boundary_layer node, since that node seems to get rid of a lot of unneeded particles? Or maybe I am supposed to be caching in the beachtank_initial geo after the wavetank? Before the OUT null? I was under the impression that once I've cached the compression node that Houdini would have all the information it needs to render the surface that comes after and wouldn't need to "cook OP" the import_fields from the DOP I/O. TL;DR Just caching compressed and particlefluidsurface I'm getting long cook times when going to new frames, so where else should I be caching before that to speed things up? I've attached a screen of my node tree to show what I mean. Thanks in advance, really trying to wrap my head around the best practices and make sure I am not missing a step somewhere.
  13. Hi i have a question regarding narrow band in fluid sims: I am using an ocean source for my flip tank as source but how do I calculate the layer size in oceansource (thought its particleseperation*gridscale*narrowbandwidth) - because my fluid keeps dropping down when sim is running
  14. Houdini Instructor

    short contract (3 months) Houdini Instructor. *must have work visa or legal right to work in Italy (work visa will not be provided)* - 4-7 experience specialized in high quality FX, demonstrated through a showreel - Well versed in the operation of Houdini and can easily relay the fundamentals on how to use and create in Houdini - excellent communication skills with both students and colleagues - rounded understanding of VFX industry and VFX pipeline - pro-active learner and problem solver - strong organizational and time management skills - previous teaching experience is preferred
  15. Hello; In a flip-fluid simulation, I would like to create a very thin layer of fluid that moves on a wavy surface. I decreased particle separation to 0.001 and I increased the "Particle radius scale" to 3, but the fluid is still thick. How can I decrease its thickness? Thanks for helping.
  16. sink FLIP

    How do control the amount of the particle kill from sink FLIP. I have a scene where I pour water into the pond, and I use sink FLIP to kill particle so it won't overflow the pond. But the amount the fluid got drain so quickly, how can I control the amount of particle that kill but a sink FLIP? I try connect it with POP Drag but it doesn't work.
  17. Hello , i have one issue with RBD Hero , it is possible to emit the same RBD hero object multiple times from particle or any objct without having to import the rbdobject node multiple times? Not packed prims only RBD Hero Object to have good floating objects on fluid tank. Becouse i try paked, prims and explode ater while, after few frames even when i play with feedback scale from Solver. Can you help me with a hit how i can manage this? Thanks.
  18. Hello, I have set up a simple narrow band flip tank and am dropping a small object (cosmetics bottle) into the tank. The issue im having is on the first frame that the object collides with the fluid it shoots a bunch of random particles out that escape from the narrow band and then re-collide with the underside of the fluid and cause ripples on the surface that I dont want to create. The RDB sim is running at a time scale of 0.05 and gravity is the only force in the scene so its moving very slowly. The time scale for the flip solver is 0.1 to get some splash, but as you can see from the attached photos its not anything crazy. Can anyone suggest a way to either stop this from happening or kill these particles before they collide with the narrow band? Im not the most versed at flip so this may be a very quick fix Appreciate any thoughts or help with this!
  19. Kinks in stretchy flip sim

    Hi all! I've got a stretchy flip sim, which is for the most part working as I'd like. It's a fluid that is being pulled apart with stretchy bands being formed. However I'm finding that when the bands become too thin, they begin to kink in a strange way, like in the attached image. I suspect this is something to do with the high surface tension in the simulation. I've tried may different adjustments to the settings, including upping the particle count, and substeps, but without any luck, Any advice or steer in the right direction to resolve this would be hugely appreciated! David
  20. I'm currently working on a melting scene where I have a number of objects that need to melt into a combined puddle. The way Im currently doing this is by converting the objects to points, giving them their attributes for density and viscosity before theyre taken into dops to run through a flip solver. From my testing and limited understanding, I believe its not possible to have the fluids as seperate flip objects because I couldnt get them to properly interract with eachother in the sim. Now for values which have attributes in the flip solver its no problem to assign these per melting object but what I want to be able to control is the particle seperation for each. I can change the point seperation in the pointsfromvolume node, and link this to voxel size in my vdb from particles node in my meshing process, but how would I also link this per object in my flip_object node in dops? cheers
  21. Hey! Imagine you are slowly closing the water tap. then the water will decrease slowly. right !!!.. with reducing its thickness. That is what i am looking for. Animating the activation key on the "volume source node" would stops, right way. but i don't want that. Even animating the particle separation is killing the details of the shape. i want it to slowly stops with some kinda details. should i animate the scale of the object (which emits particle) or is there any other way to slow the emitting region or something. any one can help me please!? thanks in advance
  22. Good evening everyone! I learned some lessons and trained at home in Houdini, and tried to make realistic fluids together in vials for honey and chocolate, other types. I looked at pictures on the Internet and carefully studied how to create bubbles, and tried to make mantra materials. but it’s not like photographs of real honey bubbles. I uploaded - a rendering image and a project HIP. Help me how to create materials correctly? hdri.rar honey_colorls.hipnc
  23. Hello; In Houdini 16.5, I would like to add "viscosity" to a "Particle Fluid" simulation using a noise pattern, so in DOP I add a "POP-VOP" node (and AANoise in it ... ) after "Source Volume" which doesn't work. Where could I apply noise to the viscosity? Thanks for helping. Viscosity.hip
  24. beach tank flip streaks

    Hello! I'm having a problem when doing a beachtank. The motion of the waves looks good, but when the waves are retracting, there is a bunch of points that stops moving and forms a line that does not move. I've tried to increase the substeps of the DOP, but it didn't make a difference. My beach has a slope and it doesn't look like there is something else affecting it. Any help is appreciated, thanks!
  25. Hey all, Ive been following a tutorial on how to transfer the UV's to simulated flip fluid and all was going well untill I added a remesh node to the transferred UV attribute which was supposed to smooth out the mesh to preserve the detail of the texture. Instead what has happened is that the UV's have gone from being seperate shells to having all their edges connected together. There is already a vertex split in the node graph which fixed the issue before I added the remesh node. Any help would be greatly appreciated, I've provided the scene file - thanks a bunch Melting_Example_v001.hiplc
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