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Found 686 results

  1. Need Help Breach Sim.

    Hello, So I've been working on a breach SIM, but I run in to 2 quite large and possibly related problems. Water spawns around my breaching object below surface level and when the object goes out of the water. The water level is lowered by the amount of particles around the object that is no longer there When this starts happening, the surface volume also disappears. Rising From Deep_6.3.hipnc The surface volume disapears at some point probably related to 1. The Whitewater SIM only takes a small vertical sliver that goes all the way down. ~whitewatersource ~simmed whitewater
  2. Hey there. i am trying to melt a spinning coin where the fluids transform into a logo when melted....i followed this tutorial https://www.youtube.com/watch?v=B3W-S0EW9xw and it works fine but when i feed the points from the coin into the flipfluidobject there is no more spinning. it´s just instantly melting and falling to the ground. the idea is that the coin spins for ca 100 frames, melts and transforms into the logo on the ground....all the tutorials for melting are for static objects but how about melting a moving (spinning in this case) object? i tried to find a way with some kind of timeshift/point deform solution but it´s not really working. would be really nice if some one could help!
  3. i try to create this effect with flip simulation but I can't.... pls help me https://www.youtube.com/watch?v=DHRSkRLJpqU
  4. Color Cache Conundrum!

    Hi everyone. I have a newb kind of question. I have a file cache of a flip sim I have done. I want to set the color on the first frame have that color "stick" to the particles and let them mix. I am using an attribute adjust color node to assign a noise to the color of the particles however the color is not sticking instead it just changes the particle color to match the noise all the way through the animation. Does anyone know how to assign the colors on the first frame then keep that color assigned to them?
  5. Hi, I'm kind of stuck with something I'm trying to achieve. If anybody could point me in the right direction, that would be fantastic. I'm trying to combine two techniques in the same shot. I have an image that drives a flip simulation. Image has two colors and each color will become a different fluid that interacts/mixes with the other one. Initially, this image was still and it was easy for me to achieve that with attributesfrommap and mapping Cd to viscosity and density. Now I need the underlying image to be an animation (only the character moves, the rest is still). I got the character animation driving the particles representing its shape using the volume optical flow technique. However, I'm struggling to find a way to merge these two systems together and basically add the character movement to the fluids mixing together generated from image Cd. This is a test project folder, which includes the images to drive the sim. motionFromAnim.zip
  6. flip simulation collision

    when I simulation fluid in Houdini, some particles just pass through the colled object. what should I do?
  7. Hello everyone! noob needing some guidance from above here haha I'm working on a flip sim, just melting a cube into a viscous liquid. The sim is good enough but I'm having a little bit of trouble with some subtle flickerings along the edge which are driving me crazy haaha was wondering if there's any technique or trick to get rid of them?, the goal is to make the fluid very smooth. Thank you very much in advance! Best! Attaching a video and some screenshot of my meshing setup. Screen Recording 2022-04-27 at 16.08.42.mov
  8. Flip River Upres

    Hello, I have tried to replicate the videos down below. However I got an issue that the sim has a hard time to remain thickness/volume of the upres layer. I could kinda fix it when bringing up the reseeding (surface oversampling) to about 10, but that will change the volume of the sim. Does anyone have any ideas regarding that? https://vimeo.com/108888186 https://vimeo.com/638633520#t=71s
  9. FLip to bowl

    Hi guys.I want these water fishes move from lower position to higher position and then fall dowon into a bowl.I have made flip source.but shy the dop net can not work? any tips and tricks well be appreciated. thanks in advanced. FishFLip.hip
  10. Flip object collider

    Hello, I would like to know why these two objects do not collide? flip_fluid_object_collider.hip
  11. Is there a way to blast things across time? Short scenario: I have a set of points, and some of them behave badly some of the time. It's easy to set an attribute on the bad points and kill them, but I don't want the pointcount to vary across time. I have an ID on the points. I would like to be able to check if a point is ever bad, and then kill it at frame 1 - so my output has a constant pointcount with constant IDs of only the points that are never bad. Possible? How? Long story: I'm using a FLIP sim to make points wander nicely across a surface. The bulk motion is great, but the border points behave terribly. I can't delete the border points during the sim, because I lose fluid volume and all my points wander off the edge. Most of the border points stay at the edge of the sim, and it's easy to transfer an attribute to them post-sim and kill them off -- but there are exceptions. Some "good" points wander to the edge and get stuck; some "bad" points work their way off the edge and join the bulk motion. If I'm just blasting the border points as a post process, those few points that escape end up ruining my pointcount. How do I smite them? Thanks in advance!
  12. flip vol. collider issue

    Howdie, my volume colider in a flip sim doesnt behave as expected. Would you mind to hava a look at it? Thanks in advance. paint_smear.hip
  13. Melting object with random gravity/viscosity

    Hello there. I need to melt a typo object from bottom to top with a fluid sim. Problem is i don´t have a groundobject/plane so when i start the sim the particles instantly fall down. i had the idea to use a point group which goes from bottom to top to give the particles a random gravity/viscosity so they don´t melt uniformly. tried to set this up in the dop network using a solver and some attribute wrangels but i don´t get it to work... would be fantastic if some one could help me with this! greetings and take care.
  14. Any other suggestions on how to take a large wavetank sim, and crop just a small swatch, to do whitewater testing on, instead of the huge tank? I need to take the compressed fluid cache, and crop out a small bit. Tried something like this which sort of worked, but the whitewater source changed completely, so I am guessing I am screwing up something? Cheers! this is the ww source before cropping - this is ww source after, completely different as if it has more curvature?
  15. Flip Simulation Collision Question

    I am trying to create a bubble using white water with simulated data in water. This may be a basic question, but my skills are lacking, so please help. Is it possible to reduce the collision area in flip simulation? I want to reduce the collision area only by the red part shown in the figure. And in case of objects moving quickly in water, there is an interpolation phenomenon when simulating white water. Any tips on how to solve it? thank you.
  16. Guided Ocean vs Wave Tank?

    Ocean experts - what is really the difference these days between a Guided Ocean and just a Wave Tank? Are Guided Oceans just legacy and no use anymore? Pros and Cons? Cheers!
  17. Hi all - basic FLIP question around detecting particles that collide. I have a simple setup (see screenshot) and I need to detect and group particles that collide with the static object in order to assign a new Cd to these collision particles - hopefully determined by either a ramp OR a texture color from the collision geo. I'm having trouble finding good references for detecting colliding particles in a flip tank / flip solver setup. I found several tutorials covering setting up a pop collision detect node for a pop solver, but I'm unsure how to translate that to a flip solver - or even if a pop collision detect would work with a flip solver. Any help or pointers would be much appreciated. Thank you!
  18. pop fluid splash

    Hello, I am studying after watching this video. I want to make a splash with a faster speed than this video. If you increase the gravity value, all particles will receive the gravity value and go down. Is it because the mask value is not applied well? Help. thank you.
  19. Hi all! I have a sim that does both, FLIP and RBD. All works fine so far, but I am struggling with caching it in an efficient way. I am using two separate DOP import streams to fetch the FLIP and the RBD and caching them out. As the sim is too high res to fit in memory that means that after e.g. caching out the FLIP I have to run the whole simulation again to cache out the RBD! There must be a better way... Any input appreciated!
  20. I'm having an issue with the Beach tank shelf tool when I try to use the Ocean Waves SOP (along with a couple of Ocean Spectrum SOPs) to seed the waves. As you can see in the video, the velocity of the waves seems to be transferred to the boundary layer of the simulation, but nowhere else, and the passing of the instanced waves seems to have little impact on the simulation, when the waves should in reality be breaking on the beach. I've already played around a lot with this and I believe it could have something to do with the velocities of the points on which the waves are being instanced, but I'm not sure. Any suggestions would be great, thanks! Beach Tank Issue.mp4
  21. Scale down ocean guided inputs

    Hi, I am trying to simulate an ocean guided flip with a maya scale spectrum (1 maya unit = 10 houdini units). Since I did not find a way to properly scale down the a spectrum , I am down scaling down all the inputs of my sim : _ The particles -> Transform SOP _ The grids (surface, vel, guided_sink, guiding_surface) -> Transform SOP + scale down values _ In the solver I scaled down all the parameters linked to the Ocean source (particles sep, boundaries,...) My issue is despite those adjustements the waves are "breaking" and not matching closely to the spectrum. It looks like they are just affected by the vel field like a standard force and not really guided. Please let me know if you need more informations. Cheers
  22. FLIP slip field control

    Hi, I'm currently working on a scene where the oil spill on an object. I need to control the slip field so I browse through any video that I can find. I found one pretty interesting, it's a flip test made by Tim Woods on Vimeo. in the comment section, he explained using DotProduct in VOP in DOP level to create Curvature Attraction. This is his explaination: Curvature Attraction is based inside the DOP network as a SolverSOP piped into the Particle Velocity of the Flip Solver. At it's basic level it measures the surface using DotProduct against a vector of 0,1,0. You can use this to mask a test that finds closest mesh position weighted by distance. I also made a mix/slerp the cross product of the surface normal (makes a downward flow normal). This helps keep the flip moving, otherwise in some cases it can slow down when you start to add upward vel to it. Can someone help me on this part, I don't know how I should wire the DotProduct also how to create the attraction from it. I would be appreciate if someone could give me a hand in this. Thanks in advance.
  23. Variable Surface Tension

    Can somebody please help me with this surface tension problem. I have a scene and i want a different surface tension to apply to different group as show above. I want the group 1 to have higher surface tension and group 3 to have a lower surface tension but my setup is not working . SurfaceTension.hipnc
  24. Water Splash

    Hi Everyone, I am trying to create a water splash with separate water trails as shown in the below image. I have created separate sim for splash and main water sim. Using object velocity to emit splashes but unable to get proper shapes of water splash as per reference. Any ideas or suggestions will be of great help.
  25. Dear Houdiniers, I am doing a heavy FX shot, mostly FLIP colliding with geometry and whitewater from that FLIP. I need to cache multiple .sim and .bgeo.sc sequences for various different SOP and DOP nets. It WAS..... all working fine, but now caching anything it seems, whether "save to disk" or "save to disk in background", doesn't work properly. In save to disk it seems to hang and when in background randomly decides to finish early and jump to 100%. There seems to be no pattern to the amount of $SF it gets to, at least none I can discern. I have tried down rezing it and allowing caching to disk to no sucess. I hope someone can help. This is a shot that may land me my first job in the industry, fingers crossed! Cheers 5D PS: haven't included .hip because it has so much cache all over the place. Should I upload it anyway??