Jump to content

Search the Community

Showing results for tags 'Simulation'.



More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


Forums

  • General
    • Lounge/General chat
    • Education
    • Jobs
  • Houdini
    • General Houdini Questions
    • Effects
    • Modeling
    • Animation & Rigging
    • Lighting & Rendering
    • Compositing
    • Games
    • Tools (HDA's etc.)
  • Coders Corner
    • HDK : Houdini Development Kit
    • Scripting
    • Shaders
  • Art and Challenges
    • Finished Work
    • Work in Progress
    • VFX Challenge
    • Effects Challenge Archive
  • Systems and Other Applications
    • Other 3d Packages
    • Operating Systems
    • Hardware
    • Pipeline
  • od|force
    • Feedback, Suggestions, Bugs

Found 201 results

  1. Retime Fluid Mesh

    Hey wizards, So I'm pretty stoked on the new retime sop but I'm having trouble getting it to work on meshes. In the attached image, flipSim_cache is 90frames and in the retime sop I'm trying to extend the length to 175frames. Problem is, I'm able to slow the animation down but it always end at frame 90 without finishing the original animation. If I turn the interpolation on, my mesh is all messed up. Any pointers would be very much appreciated. Thanks!
  2. Hello! So this weekend I cached a FEM simulation and it went swimmingly--sort of. Okay, I didn't do a .sim cache, but a .bgeo.sc cache. The problem is that the file node I have set up in the project to read the cache doesn't read what was written--it keeps recooking all the finite elements, even though it is not hooked up to anything except for the cache directory. (I even tried switching the file cache node I used to write it to "load from disk," and it still wants to recook everything. I pulled the cache into an empty file and it loads beautifully, so I know it actually cached fine. The next step in the project is to pull it in and use it to deform the original hi-res geo. How can I tell the project to stop cooking and just read what it wrote? Thanks for any help, as always-- **Addendum** - creating a whole fresh new file read node worked fine. I guess at some point Houdini nodes get tired and forget where they are? At any rate, I would love to know what I clicked that made it so forgetful, so I know how to fix it when I screw up again. **Addendum to the Addendum** - the new file node worked fine, until I went out of that subnet and back in, and then it started doing the cooking again. So, still not fixed, and the file nodes are still forgetting themselves.
  3. Source RBD objects

    How is it possible to source in RBD objects (hero) into DOP over time?
  4. First dump from a home-brew Grammar system expressed iteratively as an evolving growth system. A decade of hunting down Blackberries to their roots - to remove them from my yard; A month of looking at and sketching Blackberry growth in the wild. A day with Houdini Apprentice, and a single point of geometry to seed the system. Then just turned it on. There's fewer than 100 lines of code, and I'd guess about a dozen substitution rules in the grammar system. Emergence is an effective approach for modelling organic processes. Blackberry_h17.13.hipnc
  5. Hi guys, I'm kinda new to this software and this is my first post, after several days of trying to solve this problem: Am trying to simulation how stellar wind affects the gas clouds in interstellar space. https://www.spacetelescope.org/images/potw1106a/ (reference picture from Hubble) When new stars are born in high density regions, the ignition and radiation of these stars create winds that pushes the dust around them, sculpting away the surrounding molecular cloud. These winds can reveal this hidden star formation process and sometimes accelerate it, when this expansion compress another high density spots, this slowly collapsing cloud will form a new star. These places are also called stellar nurseries. So, i'm trying to visualice is the first parts of this process, the way stellar wind sculpts and reveal the clouds around them. I've modeled a random cloud to represent the very uneven density distribution. Where i'm having problem is in getting this "wind" to affect more the lowest density regions. I tried with a couple of fan forces in oposite directions and kinda worked, but could not get to work a mask using the density field, maybe is posible, but i couldn't do it. Then i tried a gas field wrangle to get a another velocity field "wind", from the origin and multiply it by a factor inverse to the density squared (see screenshot) This also kinda worked, but i get a very voxely looking render (video attached), maybe with a higher resolution and some blurring node somewhere could improve this. I also would like to achieve the effect that the winds is slowly expanding trough space (since the spatial scales here are huge), maybe i could bound it to an expanding sphere? (i dont like that the wind effect is instantaneous in all the scene) maybe some kind of raycast could be an option? i'm open to ideas, coz i don't even know how to begin to google that :/ That's what i've tried so far, would be really happy if someone could share some ideas or resources! Thanks in advance. pd1: another idea i would love to implement is to fake the dust colapse by gravity with some clumping also based on density (i tried with gasshred and gas surface tension with poor results) pd2: Eventually, i would like to get this expansion and subsequent peripheral density increase around to spark the birth of new stars. I don't know if is posible to create fuel from a certain density threshold or something like that. But that's a second post i guess. StarDust_07.hip StellarWind_Advect2_1.mp4
  6. Crowd Sim Popping

    Hi, I've been playing around with the demo crowd sim setup inside Houdini and wanted to setup my own based on this. I used MakeHuman and Mixamo and setup a character with animation. I got all the parts working but for some reason the animation on my character pops like the rig or cache is breaking. I've narrowed it down to being something about the retiming being done in the crowd sim but I have no idea what the actual problem is or how to fix it or even what to search for. Any ideas? Attaching my scene just in case. sim_test_v02.zip
  7. When would you use FEM over Grain? The last couple of weeks I have been working with Grains, and got a good understanding of how it works. It seems that you can do pretty much everything with this tool in case of cloth and simulation of object that will deform. I haven't been using that much time on FEM, and from my perspective it looks like a tool that has a lot of overlaps with the grain tool. It could be nice to get an understanding of where the FEM and Grain tool differs and where to use which, from people that has good experience with both tools.
  8. Hello everybody! I am glad to present you my latest tutorial “Liquid pixels simulation. Houdini tutorial”.
  9. Hi guys! I would like to share here my latest personal project. Everything done in Houdini and Mantra Hope you like it. Youtube Version: Shark_Youtube.mp4
  10. Colored Smoke with CMYK

    Last week a guy asked in the brazilian houdini group, in facebook, how to simulate colored smoke. I believe there are lots of hip files with this kind of effect, but while thinking about it, it came to my mind the possibility of using CMYK instead of RGB, since cmyk is more suitable for mixing colored things other than light. I couldn´t spend more time testing it or improving the file, but it seems to work, so here´s the hip file. colored_smoke_V002.hip
  11. Fast smoke simulation

    Hi there, I am learning about smoke in houdini and I am desperately trying to achieve an effect like this By this I mean a fast paced smoke puff that spreads out wide, like almost in a V shape. However, no matter what I do, my smoke always ends up looking very straigt. I can achieve the fast paced but then it looks even more straight I think. I tried making it faster by chaning the time scale, giving it a high buoyancy lift, using my normals as a velocity volume (in source volume node) and setting the scale of it to very high, setting the temperature scale to a higher values, etc. All these individual things work for the speed, but I keep ending up with quite a straight line, or something that isn't making sense at all. I tried adding turbulance, but this also doesn't help me to achieve that "v shape". I hope someone can explain to me what is going wrong, because I am totally lost.
  12. smaller ripples

    Hi guys, I have a flip simulations where I am dropping a rock in a vase. I would like to keep the velocity of the splash it generates, but I would like to decrease the amplitude of the waves that the flip sim creates. I've tried to play with the velocity smoothing, but it will also decrease my splash highness. any suggestions? maybe it's worth doing it post sim? thanks a lot
  13. destroying animated geo

    hello, i am currently doing some r&d for a bigger project in which i have to destroy certain parts of a transforming building. so i started to animate a building-like shape with a growing collider inside, so I could start researching how to fracture and constraint animated geo and destroy just the parts that really get hit by a collider while the rest follows the animation. it worked out quite good, but now i got to the problem that even if the destroyed pieces are laying on the ground, they still sort of follow the overall animation. I tried to put deforming to 0 in a sop solver inside dops after reaching a certain speed but that didnt really help at all.. can some of you give me any advise? thanks in advance! animFracTest.hip
  14. 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!
  15. POP Grains - Experiments and Issues!

    Hello, I have been experimenting with Grains node and shelf setups as as custom setups. I started with a sphere, then a sand castle and last was a statue. Some results were pleasant then I ran into some issues. Weird and strange behaviors such as floating sand clumps. Mainly it looks like too much force or friction. The problem that the solver feels like it is too sensitive (minor values can change things very quickly). Any pointers or advice is greatly appreciated. Copy_of_SandCastle.mp4 SandCastle_002.mov SandCastle_003.mp4 SandSolver_issue.mp4
  16. guided ocean from animated geometry

    Hello this question was originally asked here (and I have pretty much the same question) https://www.sidefx.com/forum/topic/46028/ "I am wondering if it's possible to simulate a thin layer of ocean from any given geometry mesh in houdini?" Or from my input mesh that is a deforming animated plane? It is basically wave previs anim from Maya -- I am looking to drive a flip sim with this animation similarly to bifrost guided parameters: In the sidefx forum I linked someone mentioned "- detect position of flip particle if it is below or above the surface if below the surface but the distance with the surface is below a certain threshold advect it by the point velocity. if the distance is more than the treshold it get deleted every frame." I was wondering if someone can headstart me with how to go about this implementation, does this process need to be done within the solver? Thank you all for your time! -Shane
  17. I am trying to create a solid object, with hair simulation that can collide with other surfaces. Right now I am using the "Organic mass" shelf tool, to create a solid object of a sphere. I am then applying hair (Add fur) and then adding hair simulation (Also via the shelf tool) I have also added a ground plane. When the solid object collides with the ground plane (And the object begins to deform), the hair simulation explodes. Is there another way to create a solid object with hair simulation, that will work, when colliding with other objects?
  18. CloudFX to Pyro

    Hi i created an animated cloud with cloudfx and cloudnoise node. At a specific frame i want to switch to a pyro sim and use the exact same volume as a starting point/and source - to initiate an evolving cloud. (I applied on both the cloud material) Is it possible to append to the cloud the same resolution as the pyro sim and to have no glitches when playing the change from pure cloud sim to pyro sim. What do i have to consider - or what would be the workflow? Thank you for ur help testhip.hiplc
  19. "Mimic" Creature

    Hello everyone! I am a newbie to Houdini and try to teach it myself; I hope that this is the right place for this question. Also please excuse my English as I it is my second language. I saw Edge of Tomorrow and was amazed how dynamic and alien the "Mimic" creatures looked. I tried to recreate the effect, but I get stuck on how to approach the "secondary tentacles" (the smaller tentacles following the main rigged curve) and the "growing" effect. You can see the look I am trying to recreate in the video. First (hip file)I tried to use the main curve to scatter points, get the Transform and Rotation Matrix and move them away from the curve(also tried to randomize the displacement distance or use a noise to get a little bit more "natural" behavior). However this doesnt give me the organic movement and growing behavior that I am trying to achieve. Next I tried to work with particles and somehow move them using a curve force, but first of all I couldn't get them to follow the curve properly and they also don't interact with each other. It is probably a fairly easy problem but I cant wrap my head around how to even start. I would be very thankful if you could help me; I don't need a full walkthrough but kind of a concept or a rough idea how you would approach such a project. Also if anyone is interested I will share my HIP File if I have a breakthrough. Thank you very very much for reading and have a nice day. Hans tentacle.hiplc
  20. Is it possible to use at point group from sop level, to constraint points in a dop (wire sim) with the "SBD Pin Constraint", instead of manually typing in all the points, that has to be "Constrained Points"?
  21. Hi, rebels! I`m currently looking into some Houdini flip RND and I got this shot where I need to paint friction attribute on one side, e.g the water falls faster on one side of the ground. Is this a straight forward thing or is it a bit of a pain in the "!$ due to the nature of water? I attached a test file so you guys can get a sense of what I`m talking about friction_water_test_v001.hip
  22. Hair with soft body sim

    Hi guys! I have been trying to figure out how to re-create this effect. https://www.instagram.com/p/BiMSgmaHHQT/?hl=en&taken-by=hellompc I have a few questions as to how I should go about this 1)Would I simulate the soft body first followed by the hair or simulate both of them together? 2)Using the simulate guide shelf tool,it creates a separate network that is not part of the autodop that the organic mass shelf tool creates, Thank you!
  23. Collision object in Pyro sim

    Hi everyone, I am working on a smoke simulation and i have imported my collision object with source volume into my Pyro sim. No matter how much I increase the smoke divisions as well as reducing the voxel size on colliding geometry I still get jagged edges when smoke interacts with it. I have attached a screen capture here to make it more clear. Is there any way to smooth the jagged edges or am I missing something in the process? Any tips would be greatly appreciated!
  24. Hi, I'm trying to get a rigid body destruction simulation working in Unreal 4 as a vertex animation using the Game Development Tools. I've got it looking pretty good in game now, except some of the pieces tend to randomly flip briefly as they rotate. It usually looks wrong for about a single frame or two. I've seen similar problems in sims from Maya, and it's usually been some sort of gimbal lock or euler problem. I'd usually be able to fix them by turning on unwind curves, applying a Euler filter, or by hand if it was just a few pieces. What is the best way to deal with this in houdini 16, especially with a large number of pieces? Is there a filter I can apply to the animation curves? Also (sorry, I'm still new to houdini), where would I access the animation curves on a file cached sim? Thanks in advance! Brian
  25. I have a collision object that I want to push through a particle sim area. I want to remain the small sim area (box) so the particles stay inside the tight area but once it gets hit by the collision object the particles that were affected by the object fly off. How can I achieve this? Thank you, this is the file I am talking about. Particle Collision Tester v03.hip
×