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Found 90 results

  1. smoke sim

    hi all so i've been trying to make smoke come off of a pillar as it gets broken but at the moment all im getting is this steamy cloud kind of following the debris parts , and i have no idea how to make them more refined and also to make the smoke more of a thicker trail , any help with this would be greatly appreciated, i am still very much a newbie to houdini. Wall_Fracture63.hipnc fist.abc
  2. I want to do super slow motion of cheerios falling into milk flip fluid. When I change Scale Time from 1 to 0.1, some of the collisions cause explosive behavior. Someone suggested I write out the sim files with Scale Time set to 1, but substeps increased. Then read the sub stepped sim files as if each was a frame. It appears to work, but I'm getting some flickering in the flip fluid. https://drive.google.com/file/d/17zJgRw7DtQ3W-gqnCiHXpcvGSQDxORGw/view?usp=sharing Any ideas how to fix? thanks
  3. Hi Guys! So i'm trying to do this simple flip sim where i have an emitter inside a teacup and i just want to fill up the cup. It's is definitely water tight, the only particles leaving the cup are over the top, but as you can see from my flipbook the particles just start multiplying on their own when they land in the saucer, which is causing them to go everywhere. It is worth mentioning as well that the particles are only set to emit between frames 0 - 24 so i'm not sure why they're multiplying. Any suggestions as to how to stop this would be really appreciated!
  4. Hi, Would like to know how this effect was being done, please throw some ideas or simple set up. this is the link: test_wave.hipnc
  5. Can someone please give me an indepth explanation as to why the CPU vs GPU sims look different? I have noticed when making a fire sim, GPU gives a bit more streaky and jagged sim (better licks) than a CPU sim which tends to be a bit more billowy with more 'shrooms' or rounder shapes in general. Sadly GPU crashes on any large scale sims yet I really like the look. How can I get CPU sims to look as streaky and jagged as GPU? Any tricks to stop a GPU sim from crashing? Cheers!
  6. Points follow points

    Hello everybody! I would like to simulate particles on top of pre-animated / pre-simulated (cached) points. So far I only managed to do the "transfer v attribute inside a sop solver" trick. Unfortunately it does not give me the result I imagine. Instead of inheriting only the velocity I would rather like the points to be attracted by the pre-animated points so they tumble around and follow them the animated ones. Basically I am trying to animate some points and then do a simulation on top of it to give it a more natural feel and to be able to art direct the simulation better. I would greatly appreciate if somebody could give me a hint or a solution on how to do that? Thank you! Here is my current progress (particles inherit v): pop_transfer_vel.hiplc
  7. Hey everyone, I'm happy to introduce Bullet Breaker Core, a toolkit for easy animation of bullet simulations. Link to Bullet Breaker toolkit -> gum.co/hTnq The purpose of Bullet Breaker is to allow for easy animation control of fracturing objects inside of Bullet simulations in Houdini. Bullet Breaker Core comes with digital assets to allow for ease of use in setting up and visualizing Bullet Breaker attributes. Bullet Breaker Core also comes with a brief tutorial which goes over how to setup bullet breaker compatible fracture geometries. Bullet Breaker Core does not use Houdini constraints and while it is possible to use Bullet Breaker with Houdini Constraints it is not meant to be used with Houdini constraints. Includes the demo scene file and all digital assets! Hope people find this toolkit useful! You can reach me at trzankofx@gmail.com for questions or comments.
  8. Subdivide / interpolate voxel?

    Hi guys, I'm working on some pyro simulations which require dense fluid look. I have to crush the density remapping to achieve the dense look. But the banding issue appears. So I'm thinking is it possible to subdivide each voxel to 8 small voxels and interpolate the density value? Thanks!
  9. Color in FLIP sims - milk pour into tea

    Hi everyone, I was thinking of creating a simulation of milk pouring into tea as a showreel piece, but I'm not sure how best to go about it. I have seen people using color in FLIP sims, however in all the examples I have seen, the fluid is shaded to be opaque (like different color paints mixing). In my case though, I'd need to be able to see the milk as it is poured into the tea and see it underneath the surface. Then over time, it needs to change the color of the tea. My best guess would be to simulate the liquid, and then create a separate smoke simulation for under the surface of the water. However I have no idea how I would integrate the two. Here is a reference video I found: Any ideas for this would really be appreciated!
  10. Grains Workflow

    Hello I would like to use custom geometry(like little pebble shapes) in a grains sim for visualzation rather than use popsprites or just particles dots. I also would like the grain geo to interact/collide like in a RBD sim, what is the best workflow for doing something like this?
  11. Pre foam by texture in the beachtank

    I'm trying to add foam in the first frame of my simulation. I'm using a scatter node to distribute the foam in the first frame,My idea is to inject these dots into the whitewater solver so that they are calculated dynamically. I want to do something like this https://vimeo.com/162173918. Try to make an object merge of the dots on the Whitewater source node but I can't make these dots become foam particles thanks !
  12. fur sim issues

    hi guys, i,ve recently ported from maya over to houdini been playing with the amazing fur tools and trying to simulate some fur. but my sim is too stiff ,, i,ve tried reducing the spatial scale but to lill or no effect. any ideas how to fix this guys thnx
  13. Hello! I'm using grains to fake cloth and I'm having this weird issue where I'm using a popwrangle to update my targetP (because the constraint points are animated), and it seems to be dragging the target points towards the origin? I've compared my set up to a couple example files and can't quite figure out what's gone wrong. Any help would be appreciated! Example file attached targetPointIssue.hiplc
  14. Hi all, I'm trying to create some physically accurate bullet sims using real world values for mass/density and friction, so I've been looking at some engineering tables for friction coefficients: http://roymech.co.uk/Useful_Tables/Tribology/co_of_frict.htm What I'm confused about is this: It seems that real world friction is calculated based on the coefficient of friction between two objects, eg wood & wood has a friction coeff of 0.25 - 0.5; wood and concrete 0.62; wood and metal 0.2 - 0.6. So friction is not a material specific attribute, so if I have 3 houdini objects, one wood, one concrete and one metal, how do I create realistic friction settings for each combination when I can only set a single friction value per object? Is it even possible? Also, how does Houdini calculate friction coefficient between two objects? Does it multiply the friction values? Or average them? Any help is much appreciated Thanks in advance!
  15. Hello, i am currently working on my final student projet where i make a plane crash with Houdini. I base the workflow of this project around the RIGIDS III tutorial by Steven Knipping. Everything is working fine until i bring in a simple glue constraint, and when the simulation gets activated at a said frame the simulation simply does not happen. It works when i disconnect/disable the constraint. I already tried to unpack the alembics upon importation with the alembic node but that didnt change anything. What is weird is that everything was working fine when i used the model given with the course. I haven't really found anything that helped me online, so hopefully one of you can help me with this issue, i would appreciate it A LOT. I will attach the files down below. Thank you ! plane_sim.rar
  16. OpenCL Sim caching with multiple gpus

    Hi, is there anyway to cache my pyro sim in opencl with my 4 gpu (4xgt1080)? i couldn't find any preferences on houdini or topic in search. Thank you.
  17. Guided Ocean Layer SIM missing frames

    I'm trying to sim waves lapping up onto large rocks jutting out of an ocean. The sim appears to be working. However, when I write out to a bgeo sequence, some of the files have low byte counts, and are correspondingly missing when you play them back. This was simmed on a machine with 24 processors and 20GB of ram. I'm going to try to increase memory to see if this fixes the problem. But it would be helpful if the hip file could write out more informative diagnostic information. How would one go about doing this? As the geometry rop doesn't inherit any log info from the source DOP. thanks devilsRock.waveSim.h16p5p378.v007.hipnc
  18. adding turbulence to flip sim

    Hey! What is wrong with my setup? I am just trying to use a source volume node to add turbulence to my sim. However, I can't get it to work! Any help would be amazing. Thanks, flip.hipnc
  19. fetchdata DOP

    Hi, I wanted to know if the 'fetchdata' dop can be used to fetch the data from outside the dop. I'm trying to fetch a cached particle simulation into my pyro sim but for some reason it cannot fetch the data outside the pyros DOP. If the particle sim is in the same pyro dop then it fetches the data.
  20. Cable Overheating

    Hi everyone, For an upcoming project, I need to create the effect of an extension cable overheating. ie. holes being burnt in the plastic casing of a wire and then smoke emitting from them. This is a good reference, particularly the shot at 1:26 https://www.youtube.com/watch?v=jGPkkOU3Uf8 The problem I am currently having is that for smoke to emit from these little holes, the source volume has to be really tiny. This requires a ridiculously low division size just to get the sim to work, making it impossible to easily preview the simulation. I'm thinking there must be a better method for doing this, so if anyone has any suggestions, I'd be happy to hear them!
  21. Hi All! Are there any ways to optimise/reduce the file size of Houdini caches. I'm caching a (very small) FLIP fluid sim with a 'File Cache' Node at the moment and each frame is about 100MB. Multiply by 500 frames and that's a BIG cache! - not to mention the time its taking! I am sure it shouldn't be this large considering this is only a very small fluid sim so any tips would be great! I know a lot of people have this issue with sims so hopefully kind people can help us out! Thanks in advance!
  22. Hi! Houdini beginner here, I am trying to make a basic rain sim of rain interacting with an object and splashing on the ground making puddles. I am having a problem with the particles splashing on the ground, they are acknowledging that the ground is there but 50% of the particles splash against it but the rest go through it and splash just under it, i have tried using different things for the ground like a groundplane and geo but i keep getting the same problem. Any suggestions or help would be amazing! I Have attached the scene file if anyone would be amazing enough to have a quick look? Thank you in advance! Rain_001.hipnc
  23. Hi there, I'm learning how to make guided ocean layer sims and I have a couple of questions: 1 - I'm not familiar with caching system from Houdini. In my guidedoceanlayer_sim I have output name - $HIP/sim/$HIPNAME.`opname("..")`.$SF.sim - first newb question, should I use .sim or .bgeo? 2 - I've copied that name and after saving to disk, I 've pasted as relative references under DOP Network - playback simulation. I should see the sim, but I only see last frame of the sim and a bounding box around boat 3 - Under Ocean Source wavetank I have this expression under center - centroid("../mergefollow", D_Z) - How can I add or subtract a value since I don't need so much detail in the front of the boat and need more at it's back I'm learning Houdini so please be gentle. Thanks!
  24. Hi there, quite new to Houdini and I'm struggling to find documentation for something like this. I have a scene with a building where there are multiple fires starting at windows of varying sizes. This means I have different source volumes (fuel & temp, and a pump) for each window. I want to be able to render the pyro from each window separately and perhaps even have dynamic resizes for each source. The only way I could imagine doing this would be if it was possible to have multiple smoke object nodes that can reference different source volumes (the fuel & temp, and the pump). I saw that clustering exists but from what I understand it only accepts point sources? I am using a fluid source node building SDF from geometry to create the source volumes. What would be the best way of doing this? Thanks in advance and apologies if this has a very simple answer.
  25. RBD Fractured Obj with FLIP?

    Hello! I'm doing R&D for a project that will involve and egg breaking, releasing the yolk/white. Right now I'm just trying to get the principles down. I am currently just testing fluid inside an egg (making sure it stays inside when it's supposed to and falls with the egg in gravity) and am having issues with the fluid disappearing or leaking from the egg. I am used to using rbd packed objects for destruction so I started out my workflow with the egg as an rbd packed object, but saw some examples on here that suggested using an rbd fractured object so I have tried that as well. When I use the egg as a packed object, the fluid seems to just slowly disappear over time, and when I use a rbd fractured object the fluid sticks to the eggshell on the second frame and then flies out. I know the eggshell is thin geo for being a collision object (it is accurate to a chicken egg), but even when I thickened the geo I still had fluid disappearing. Any advice regarding using fluid inside rbd objects would be appreciated! egg.zip
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