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Found 76 results

  1. Hi; I have a pre-fractured vellum cloth that is fixed in place using these attributes: i@stopped = 1; i@gluetoanimation = 1; I have some particles that collide with this cloth, and they change those attributes to tear cloth pieces at that collision place. The problem is activated cloth pieces never rest, and they pass through each other in some frames. Thanks for helping. Vellum_Particle.hip
  2. Vellum Cloth Eyelit

    HEY everyone, I'm trying to recreate a metal eyelit in a cloth and I am going about this using simple cloth. so far I have a pretty nice working file but my cloth starts wrinkling almost right next to the eyelit. I am trying to make a fall off on the outside radius of the metal eyelit so the fabric has more integrity to it around the eyelit/is more stiff and then gets more flowy further away from the eyelit. I am also seeing intersections with the cloth and the eyelit ( I think I need to model the eyelit properly so it doesn't intersect from frame 0 into the cloth or it wont recognise that it's a collider) Anyway I'm very, very new to houdini and have come from c4d so I was wandering if you guys could take a look at the HIP file I've uploaded and tell me if I have the correct setup and how I can make the cloth around the eyelits more stiff so all wrinkles eventually falloff to 0 before it hits the eyelit. Using vellum simple cloth btw with attach to geo constraint. Cheers eyelit.hip
  3. Hi; In a vellum cloth sim, I would like to pin some points for some frames, and then unpin them gradually. I created an animated group called "pin" and added a "pin to target constraint" inside vellum solver, but it doesn't work. Thanks for helping. Pin to Target.hip
  4. Hi; In Vellum , is it possible to change the shape of input geometry, over time? I have a line in my scene that grows (in length) over time, and I would like to use it in vellum-hair, but it seems that vellum just uses first frame. Thanks.
  5. Vellum Hair Break

    I've managed to get the vellum hairs breaking quite nicely - but I wonder what the breakthreshold is compared against in order to determine that it has been reached. Any ideas?
  6. Softbody, FEM or Vellum?

    Hey .Hipsters, I'm quite new to houdini and at the moment I'm struggling a bit. I have an animation of some Cells, which pop out of some pores. Now I'm not totally sure, how to start. My Cell-animation would come as an alembic. 1st: Is it possible to let the Cell push through the pore like some softbody and has some kind of target / end-state. 2nd: How to acchieve the pore-stuff. Vellum Softbody or FEM. Would be cool, if somebody could help me out greetz natnat
  7. Hi, Iam trying to figure out how too simulate curtains with Vellum , i have and animated pin constraint network but it does not seem to affect my final result , did i forget to emplement something? Anyone can help me out? Thanks in regards curtain.hipnc StartGeoV2.obj
  8. Collisions in Vellum

    I want to change the texture color of colliding objects in vellum. I have been trying to figure out if there is a way to access the collision data from the vellum solver but I can't find anything in the documentation. In the geometry spreadsheet it shows a column for 'hitnum' but the values are all 0 even when my geometry touches. Any tips would be greatly appreciated. Cheers inflate-test.hipnc
  9. Hi everyone, my name is Tomás and I'm new to the forum. I'm creating a fur sim for a chimpanzee using the Guide Simulate node with the Vellum solver. The chimpanzee will later be animated. The sim works fine but I can't find a way to make it keep its wild messy look. The guides do keep their shape (bend, guideinit, etc) because I increased the constraint iterations and the bend stiffness. But I can't find a way to make the hairs keep their direction. In other words, once the gravity affects the guides they all go too down. So I want a way to keep the original shape of the hair a bit more. I could tone down gravity or the mass of the guides but that would make it look as if it's underwater or something once I animate the chimpanzee. Increasing the constraint iterations to a ridiculous value would maybe fix this but at a high cost to sim time, same for stubsteps. Increasing Bend Stiffness to billions and billions doesn't seem to help either. Obviously, I don't want the hair to be hard as rock. I want it to behave this way because it's light, strong and covered in dust and sweat, if that makes sense. It's also important to note I committed the noobie mistake of not resizing my mesh after exporting from Maya which works with different centimeters instead of meters. Meaning my monkey was more than 100 meters tall. I believe I already fixed this by going to preferences>Hip file options but I did this after creating the simulation so I'm not entirely sure if everything was resized correctly. Attached are 5 images: the guides at frame 1, the guides at frame 73 (3 seconds into the sim), a render of the fur at frame 1 (the way I like it), a render of the fur at frame 73 (the way I dislike it) and a reference image for the sort of hair I'm aiming for. I also added the project folder. ApeODForce.zip Thanks in advance!
  10. Cross-posting from SideFX...per point friction works great, except I can't get it to workwith balloons (pressure contraints). Any ideas? HIP files attached. vPerPtFriction.hiplc
  11. Just wondering if there are any general tips/best practices here. Running sims on some very small/thin geo and getting a lot of artifacts/broken sims. Any advice is much appreciated
  12. Hey there, i was wondering if any one to could me figure out how to achieve this affect, this person was kind enough to share this setup but I'm no closer to achieving the same result. I've created the Cd attribute, ive attched my working hip file if it's of any use. Any help would be most appreciated VELLUM_ANIMATED_CD.hiplc
  13. Hi; In a vellum cloth simulation, I need to keep the original shape of my cloth object as much as possible. I tried to increase bend stiffness and stretch stiffness but it doesn't works. Later, I would like to paint an attribute like "stretchstiffness" on that cloth, to control areas that I want to be more stretched... Thanks. BaseMesh.bgeo Vellum_Cloth_01.hip
  14. Hi I was trying to create an effect of cloth pieces sticking to an animated object on contact. However, it seemed to release and re-attach every substep. Sometimes, they "creep" on the collision surface. These are the goals I tried to achieve 1. Dynamically attach to deforming collision on contact 2. Dynamically delete the paper if they fell under y 0. (done, thank to Toadstorm's post 3. Make the attached points static (pin to animation?) if possible, to reduce calculation cost. Here I attached the hip I'm working on. test_vellum.hip
  15. I know their are already a lot of threads on this topic but I can't seem to find one that matches my situation. Maybe i'm approaching this all wrong by using pin to target to begin with. I would like to create a raffle machine type effect where a very long stream of tickets come out of a slot into a box. Right now I am using pin to target with a geowrangle inside the vellum solver to change the stiffness value to a low number as the tickets enter the box. if i make the stiffness value a really tiny value this will work and prevent the tickets from getting pulled into the side of the box but it seems like i could take a better approach. any ideas? thanks in advance! lottery2.hip
  16. Hello, I'm trying to create a burst of feather when a bird hit a tree. So I'm trying to spawn the vellum feathers from a burst of points generated with a popsolver but it doesn't work. Tried 2 things: Multi-solver and instance points directly in vellum source. Anyone have an idea of how to do that? Thanks in advance!
  17. Hi everyone, I am sharing this simplified version of a project of mine cause I have an issue that is really baffling me. It's a hair simmulation, just one hair which I am manipulating its pscale through SOP solvers to create some worm like movement, It works completely fine as long as I keep the system with 1 substep, but if I increase the number of substeps it goes ballistic! I have other solvers that really polish the movement of the worm they all work fine, as long as I don't increase the number of substep to more than one. Is like the SOP solver multiplies its effect per substep. I have no idea what could be causing this, worse I don't understand the why and that really bugs me. Any help would be really appreciated. Best, Nicolas. Edit: I believe its the internal collision being multiplied, or calculated in each substep in the SOP solver, but no so such how to address this yet. Edit 2 : to clarify when the behaviour is acceptable. VellumSubstep.hiplc
  18. Hi; To pin some points on a vellum cloth, to an animated geometry, I tried these steps: 1) I add a “Vellum Attach to Geometry” SOP. 2) I grouped boundary points (“pin” group) on my cloth geometry. 3) In “Target Path” on “Vellum Attach to Geometry” SOP, I set path of my animated geometry. but it doesn't work ! Thanks for helping. Vellum_Pin to target.hip
  19. Hello, I am trying to find a way to generate a "collision texture" on a vellum cloth object. To illustrate imagine a red crayon ball colliding with a cloth. Is there a way to paint the cloth where they collide?
  20. Vellum - cloth on fast moving objects

    Did anybody have any success with vellum cloth on fast moving objects? I'm doing cloth on a character, who is free falling. It's done by an animator and speed-wise, it might be slightly overdone, but there's no way to change that. Simulating cloth on the character using Maya nCloth, I got proper results, but it was still nCloth and therefore slow and painful. I recreated the setup using vellum, but no matter how much I increase substeps, everything is exploding right away. It is working fine with a localised version, but I was wondering if there is a special trick or anything worth considering when using Vellum with fast moving objects? (Unfortunately, I cannot post the scene file)
  21. Fairly new to Houdini and I feel like there must be a trick to this- how to get accurate UV's from Vellum's Post Process node for export into an Alembic. I create my UV's at the top of the Vellum chain before sim- let's say it's a grid object. The last step in the Vellum process is obviously the Post Process node where you can subdivide and extrude the object. This screws up the initial UVs as now there is way more geometry. Applying a UV texture after this doesn't work as it recalculates every frame. How can I make this work correctly?
  22. Vellum Questions

    Hello! I had a few questions about vellum. Whats the benefit of creating constraints in sop vs. dop? Is it possible to setup vellum and only create the constrains at dop level? It seem strange to have to switch in and out of my dop net to change values. I seemed to be able to get most constraints working in dop, but it seems the cloth constraint needs to made at sop level. Also, how do I animate values? I see there is a vellum constraint property node, but how can I animate values for a pressure constraint? It seems like the constraints are created first frame and not updated. Thanks in advance.
  23. Vellum Drape Curtain Simulation

    First off I am new to Houdini, but I am doing everything I can to learn what I can about it. I have bought several online classes to go through along with signing up for a few patrons to learn from also. I don't have any issue doing the research need to help me learn how to do this effect. What I am attempting to create is a cloth simulation of a Austrain Drape to use in C4D for a scene I am working on. I have been trying different whys to pin the drape for the simulation, but haven't been successful on achieving the look of the drape like the photo I have attached. If anyone could offer some insight into how I could achieve the "Swag" look in the photo I would appreciate any help or insight in how someone with more knowledge about Houdini would go about creating this. I have found the best way to teach myself new software is by struggling through real world use cases that I will be using this software for. However it helps if someone may bring something to your attention that you wasn't aware of. I have also included my .hip file which is a very basic vellum simulation with some pinned points. Drape.hiplc
  24. Fur and snow (+hip)

    Hi everyone! The past week I worked on a personal project for learn something about hairs - vellum. It's my first project ever with hairs so I guess is nothing special but several people asked to see the hip file so here it is. Final result: Hip file (I had to recreate it but it should be pretty much the same): groom_clumping_03.hipnc
  25. Hello houdini wizards! I am playing with Vellum and trying to get the dynamic glue constraints to work. The documentation is about 1 very small section and I did what it said to (like creating the glue inside the solver and setting the Create Constraints drop down to Each Frame) but it does not grab the cloth. I played with distances and groups but no luck. I don't have a specific scenario at the moment so no scene file really that cant be set up in 2 minutes, just a grid as the cloth object, a sphere (fed into the collision input at the sop level) that dips down close the grid and then moves back up. The intention is to have constraints be created to grab the cloth within the set distance, pick it up, pull it, and then release/break the constraints when I want/need to. The breaking I can assume is pretty simple using the broken attribute in the Constraint Properties but I cannot seem to dynamically create constraints to grab the cloth/grid. Any help or knowledge you can give is much appreciated! I was unable to find any example files on the subject either but I did see the demo of it being done (https://vimeo.com/313872854) around 24:50. And again, thanks in advance for any advice you can give!
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