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Found 318 results

  1. popAwake with Vellum Grains

    Hey All! Question! Does the popAwake node work with Vellum Grains? I am placing it after the vellum source but it doesn't seem to have any affect? I'm not sure if i've made a mistake or if the popAwake node simply doesn't work with vellum? Thanks!
  2. Hello guys, So I have been trying to make a cloth collide with an animation sequence that is changing topology. I started with vellum and I hit a wall. Apparently, Vellum doesn't handle collisions with changing topology stuff. So I need to find a solution around this. My animation sequence is converted into a VDB and what else beside vellum can I use to handle the cloth? Any other ideas? Tx
  3. Hey all, I have some guide hairs in vellum and my orient (point-)attribute which is generated using the guide deform sop is "flipping" (sign changes on orient vector components). This causes the guides to freak out during simulation, showing randomly changing length, jittering and weird behaviour etc. Knowing that vellum needs a stable orient attribute to produce stable sim results, I tried to delete that orient attribute coming from the guide deform sop and instead let it be calculated on the vellum constraint node using "compute missing orientation". The values are somewhat the same and somewhat also different, but I also see some "flipping" orientation values from frame to frame on some guides. If I disable the orient attribute on the guide deform sop (create orient attribute off) and on the vellum constraints sop (compute missing orientation off), I assumed no orient is calculated for my guides, but to my surprise, I still have an orient attribute present after the vellum constraints sop. The even bigger surprise was, that this orient attribute produced a totally stable sim. This left me rather confused, and I hope you guys can maybe shed some light on whats going on here. Why is my orient attribute flipping, how can this be prevented, and what (where) is the best way to calculate a stable orient attribute? I unfortunately can't provide a hip-file showing the issue cause my current project is under NDA, but I still hope you guys can make some sense of what I say. I am using Houdini 18.5.392. Thanks in advance and all the best, Scratch
  4. Vellum-only jobs

    Hey hey I was wondering if I could get a job knowing only Vellum ( +DOPs and SOPs, maybe some VEX ). Would I have to be a master at it or could mid-level be appropriate? Thanks
  5. Hello guys, I am draping some kind of dress around my model. It works fine but then, when I start my sim and my model starts walking, the dress doesn't collide at all. Everything is connected properly, I am following the Vellum Drape masterclass. I am not sure if this is the reason but the topology of my model is constantly changing each frame. Could this be the reason and if yes, how could I make it not change? I tried point deform but that is not working. An issue I think is that the arms of my model sometimes merges with the hips as it is walking, but this is wanted. Any ideas? Cheers!!
  6. Hello guys, I am draping some kind of dress around my model. It works fine but then, when I start my sim and my model starts walking, the dress doesn't collide at all. Everything is connected properly, I am following the Vellum Drape masterclass. I am not sure if this is the reason but the mesh of my model is constantly changing each frame. Could this be the reason and if yes, how could I make it not change? I tried point deform but that is not working. An issue I think is that the arms of my model sometimes merges with the hips as it is walking, but this is wanted. Any ideas? Cheers!!
  7. hi all ! I have a basic vellum grains setup. I need to modify the clumping to make the grains stick together less and for the grains to move more freely. Any suggestions which setting in the grain solver I should be modifying?? Thank you!
  8. updating vellum constraints dynamically

    Hey all! I was hoping to get some help figuring out a way to update the stiffness value of a vellum constraint geometry across the frames of its simulation. I can write an attribute wrangle like the one pictured and it will update the starting frame and the simulation bakes from there and plays as though the values werent changing at all, much less becoming negative. I tried dropping into the vellum solver and seeing if I could figure out anything in there but nothing seemed to work. Im still pretty new to houdini so I expect it to take some time but I was hoping to eventually take whats done in these two awesome videos and merge them into a project where a genetic algorithm produces tensegrities that update their stiffness over simulated time in order to deform in ways that cause them to (hopefully) roll towards a target. Hip file of the simplest version of the problem is attached in case it helps! Thanks for reading!!! VellumConstraintsHelp.hipnc
  9. Vellum cloth and frequency

    Any Vellum experts? Spent the entire day trying to get a desired cloth simulation. What I am after is a simulation that has variety and randomness in the 'frequency' of the waves or ripples. Something you might see in a very large billowing sail. Unfortunately there is no 'frequency' parameter I can find. I've tried playing with subdivisions, turbulence, roughness, pulse length, etc. I am using a single POP Wind force. Attached are my settings and results so far. If I could some how combine the attached result with random, higher frequency waves or ripples that would be ideal. cloth.mp4
  10. Houdini Technical Artist

    Hi there, Swivet Studio is looking for some help on a short project. Essentially we need to create three animations of three varying but similar shapes. Each shape uses the same principle technique but should still feel unique. Essentially, imagine a round rubber phone cord that uncoils on itself to resolve in a straight cord. Please see below a very very rough concept. We are looking for something that has more life and realism to it. I guess most likely using vellum. We are only looking for the technical build as the rendering lighting etc will be handled on our end. We are based in Vancouver but remote work is ok. For more information on the project please get in touch at jobs@swivet.studio Please also include your folio/showreel, day rate, and location. Thank you RnD_01.mp4
  11. Hi, I am trying to do a hair/fur sim. The issue begins when the curves interact/collide or go inside the collision object. I have created a simple example file belowvellumHair_Colision_Issue.hip, where the animated sphere with hair, goes down the grid and the hair curves get stuck to it in its surface . Is there a way, I can get the curves to detach at certain stretch distance and get it back to this original shape ? Please have a look at the files below, if I am not clear. Thanks in advance for your help
  12. Hello, I have been making several attempts to accomplish something like Matt Taylor's Seeds concept https://youtu.be/vUvEy37LhqE I have tried a couple of approaches including using a multi-solver but no luck. would really appreciate any input that helps! Motion_Graphics_Designs_By_UK_Based_Artist_Matt_Taylor.mp4 Houdini_Vellum_growth.mp4 Spheres_growth_v001.hip vellum_grains_growth_v004.hip Spheres_growth_v002.hip
  13. Vellum optimization

    For one of my projects, I am using Vellum hair to simulate my tree branches, but simming gets really slow. To make my curves stiff enough I need to bump substeps to more than 3 and also constraint iterations to more than 50k and obviously, simming gets really slow. I am not sure if I am doing something wrong that I need to bump numbers so high or this is normal to wait so long for vellum simulations? Main settings I am changing are stretch and bend. Before - I made my tree real life scale, but even now, when I scaled it a bit down, I still need to bump my constraint iterations to more than 50K. P.S I have 64GB Ram and Ryzen 3900x, so I am not sure if my hardware is not good enough to sim it.
  14. Hi. I'm going to try vellum grain! After creating vellumsource in dop 1. Put only geo(../GEO) source in the sop path of the source and 2. Put geo source in sop path and constraint(../CON) source in constraint sop path in two places. Will the vellumsolver work differently? When I test, the result value seems to be the same, but method 1 is wrong, and I heard that the constraint source must be added to the constraint sop path like method 2. If there is any difference, please let me know what it is. Thank you.
  15. Hi. So I've got some Vellum experience but I'm very fresh to Houdini in general(Just to do some work in there, but it's been 10+ years since I did it in earnest). So I'm trying to 'kill' world space motion on Vellum, thus only picking up the character motion. I've found 3 ways to do this. But I'm not overly happy with any of them. I should specify that this is for Curves! For Cloth one of the solutions works pretty well. 1. Vellumrefframe. This node should do exactly what I want, but unfortunately it does not kill all motion, and it's highly susceptible to settings. A higher resolution or mass means the node is way less effective. Maybe I'm using it incorrectly? 2. I have an attribWrangle and an inverted transform node that esentially allows me to use sliders to control the kill motion in each axis. This is something that I desire in the final version of this. This particular one works decently and it's easy enough to hook on anything else in the scene to move in reverse. Can't say I love the idea though and if we wanna simulate anything else in here, or use different values on different characters, or even layers, it'll be very hard to manage that. But it is a bridge solution to something better. 3. A vellumAttach constraint with 'velcotyBlend' somewhat works. But has the same issues as 'vellumrefframe'. I'm guess it's done in a similar fashion, but haven't looked into it. Overall it almost gets me all the way there. 4. Lastly a vellum Pin constraint can be used for cloth and generally works quite well. It doesn't work for hair(as far as I can tell after looking around), however setting the pin type to 'soft' makes it "work". But with that being said it basically just attaches the entire strand to the character so it kills too much dynamic motion from the character. What I would love to have and just haven't been able to figure out is a way to solve this in POPs(or any way), where it can be calculated per point. That way the motion could be killed per root point, and controlled using a envelope value attached to a slider. So essentially #2 but without actually moving the character around and controlling it per point instead of for the entire character. That way it could be a choice to do it for the whole character(with the roots all inheriting the Center of the character), or per curve. I haven't been able to work out exactly how to negate all motion, I've gotten a ton of weird results when playing with pointvelocity nodes and trying to control velocity and target velocity. I've tried mixing in air resistance and acceleration but I think it's just due to my inability within DOPs and POPs in general I can't get that to work. I've added an example file that showcases #1 and #2. I left #3 and #4 out since they are similar to #1 really, and yields similar results. In this particular file I expect No dynamic motion at all on the curve. For those that are familiar with maya, this is easily achieved by parenting the Nuclues to the object driving the simulation. There are also several other ways to achieve that within Maya, but I'll skip those since this is all about how to achieve that within Houdini Any help is greatly appreciated! Cheers / Henrik kill_motion_example_v1.hip
  16. Dynamics Tendrils Anemone

    Hi Houdini Magiciens Anyone know how i can do that ? I know how made tendril /anemone with hair but i don't find the way to made collisions like in this vidéo. It seems like cloth. Thanks a lot for your help !
  17. Not long ago I was tasked with a simulation of bags of hard candy falling and splitting open on the floor, with the candy of various shapes and sizes spilling out. This turned out to be way harder then I thought. There is really no built in way for vellum and bullet dynamics to interact with each other in Houdini. After searching the internet, I did find one tutorial on kind of faking the interaction, but it seemed overly complicated to me. So after a bit of R&D I came up with this setup. Its very simple and fast, and solves both the vellum and bullet sims in one network at the same time: It basically works by importing the RBD geo into the vellum collision solver, and the vellum geo into the bullet solver. The mass of the RBD has to be faked in somewhat, so it interacts with the cloth in a more realistic way, but that's it! See hip for example: vellum_x_bullet.hip
  18. Proceedual Concrete Rebar

    Hello, I have question. I couldn't understand how to weld the line inside fracture geometry... It often goes through objects. Is there anyway for to do that..? Or anything tips to reach his flow for me? Thank you Concrete_Rebar.hipnc
  19. Membrane tearing

    Hi gang ! Here is my latest vellum file, I played around with noises and constraints. My goal was to emulate a membrane tearing, much like a burning film: You can download the hipfile and play around with it tearing_share.hip
  20. Hi everyone. I'm trying to create a setup that instances a few models randomly as vellum soft bodies. I want them to spawn four at a time, every twenty or so frames. I'm almost there I think- however my current solution involves using a switch that picks a random model based on time, so I always end up getting sets of four of the same model for every round of instancing. I feel like the solution should be relatively simple, but I don't mind changing my approach significantly if it's necessary. I've attached a .hip file and an image. As you can see in the picture, there are very obvious groups of objects that formed at the same time: VellumInstancing.hipnc
  21. Vellum Weld (multi cloth)

    Hi folks, Vellum_Weld2WeldedCloth_review.hip Why?
  22. I have a Vellum setup that is working great, until I change one small parameter... I'm using an initial RBD sim to hover 4 low res objects in a big group in the air. I then turn those objects into Vellum cloth, so I can drop them in a big bouncy pile on the ground. Lastly I deform the 4 low res objects with a Point Deform SOP onto the high res geometry. This works totally fine when I only scatter one of each object. The problem quickly appears when I scatter more than one of each object in the initial floating RBD pile. I sort of understand why this is happening, but I can't get my head around fixing this procedurally. I think the high res objects can't be moved into the position of the low res geo because (once scattering more than one of each object) there is no longer a name (or class?) to define each and every object independently. I am stumped in finding a way to fix this sensibly without me having to manually make multiple copies of each object with independent naming. Any ideas would be greatly appreciated! Scene file attached. Vellum_Low_To_High_Res_Deform.hip
  23. Hi everyone Im trying to get vellum dop system to emitt particles only between certain frames (Please see attached picture) Is there any ways of controlling vellum dop so that it triggers the simulation only at specific frames? something like $SF>11 & $SF<16 that one can use in the POP source's impluse activation? At the moment it seems to only accept one rule of emitting at a particular frame and it does not stop emitting I tried setting the emission type to continuous but that doesnt work either Thank you
  24. Vellum Cloth Stitching Has Jagged Edges

    Hi Guys, I have been working on a cloth simulation in vellum where im making a pattern using a curve and then using those curves to dictate where the cloth will be split up into separate pieces using an edge fracture. Im then trying to have all of these pieces stitch together to make one whole connected piece of cloth that is made up of all of those pieces that were cut out. I intend to texture all of the separate pieces individually so currently i am using the piece attribute created from the edge fracture and then have converted that to groups to later be used in c4d to texture. The problem i am running into is that the edge fracture is making all of my intended seams jagged. I feel like the edge fracture probably isnt the right way to go about doing this as it seems that its more geared towards RBD and destruction but havent been able to find a solution. I would also be curious what the best way of stitching all of the pieces together would be? I am using a vellum stitch constraint at the moment but also struggled to be able to get the seams of the pieces I had cut out to stitch to its respective piece. Below is the render as it currently is, you can see all of those jagged edges. Im still quite new to houdini so any advice or knowledge you guys have would be greatly appreciated. I have attached my scene file below if anyone wanted to have a look. PS. This is my first post on the forum so if this is in the wrong spot please let me know. Cloth_Experiment_01_v08.hiplc
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