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Found 165 results

  1. Simple RBD hanging

    Hey everyone ! I'm miserably failing at making a simple dynamic set up : / I'm trying to hang a RBD object at the end of a rope. I can't get it to work with wire solver and bullet. I've only managed to attach the rbd at then end of the rope, but the attached rbd isn't affecting the rope. And with vellum it works, but I don't want a soft body object. I tried with vellum, thinking I could stiffen the softbody until it looks like a rigid object, but vellum bugs with I reach high stiffness value ! And anyway, I don't know how to replace that softbody by my final object : / If someone could help me back on the correct track, that would be great attched is a hip file with my 2 failing attempts.6ril_RBD-hang++.hipnc
  2. Hello, I'm just getting into vellum and the solver seems fast and cool but I'm trying a sim here where the geometry tries to attach to its collision geo, but that ends up being very jittery at the end with what seems to be no loss of energy. I've uploaded a scene file. I've tried to set @v to zero at the end and that still hasn't worked. What're the steps to making this solver behave? vellum_basics__jitter_02.hip
  3. Hello everyone, the project > I'm working on short animations of a shirt flying in the wind. I decided to use houdini to learn it and use the new vellum solver. I managed to have really nice and quick result for most of the shirts but one of them give me some troubles.. problem 1 > One of the shirt is more like a polo so I would like to set differents constraints on the collar to make it more stiff than the rest. I tried to make groups and merge them but I think I'm missing something because it's not working. I can't find any related topics either.. maybe you guys can give me a clue on how to make this work ? I'm ready to experiment I just don't know where to search anymore.. problem 2 > On the same shirt there is 2 buttons. I'd like to glue them to the shirt for them to react like rigid body and follow the shirt mouvement but I don't understand how I can do it and how to place those news constraints in the graph.. First screenshot is a view of the collar and the buttons placement. It's a model from Marvelous Designer. Next a screenshot of the network view and third a view of the collar being not stiff enough ( : I can only do screenshoots of the shirt and can't really share my hip file because the design of the shirt is not supposed to be released yet. Thank you for the reading !
  4. Vellum Pin to Target

    Hey, Is there a way to constrain vellum to deform animation and then lose it over time? I'm trying to animate the "breaking threshold" inside the vellum constraints after setting the constraint type to "Pin to Target" but it doesn't seem to be doing anything?
  5. What is the best approach to make quasi-hard materials like metals from vellum cloth. I am successful with tweaking stretch and bend plasticity values but the grid still feels quite flappy. Help on how to take the soft, cloth like feel out of it to make it feel like a hard metal sheet. I am looking at this as alternative to the RBD approach to creating dent or bending in car crash situation or even metal pillars. Help would be very much appreciated
  6. Vellum tangled office blinds

    Hi there, This is a bit out there but I'm trying to remake this effect produced in cinema4d using Vellum: The blinds were simulated then looped and baked to an alembic, then I attached the strings to the edges simulated them, making them loop using a pose morph tag. I was wondering if there is a way to do this in Vellum all at once having the strings effect the movement of the blinds, with the whole thing being a seamless loop. Basic starting point for vellum would be a simple flag I know, but does anyone know any tutorials that would cover attaching multiple cloths together with vellum hairs? Many thanks, H
  7. 2D vellum Simulation

    Hello guys , I cant find an attribute or something in vellum to make it avoid movement in one particular angle or i'm missing it. I want to simulate a spring in a 2d domain I only want to run the simulation in Z and X and avoid movement in Y axis Iwant to prevent this from happening: Is it possible ? thank you all in advance for your help!!
  8. Vellum - Match Animation & Gravity

    Hello everyone, I'm currently playing around with vellum and came across an issue I'm not able to solve alone. Some Grids are falling on a collider and should be pulled in different directions at a certain frame. When the pressure is to high, they should tear apart but thats hopefully an easy thing with “weld points” and edge fracture. The main problem is the animation: As soon as I tell the vellum constraint to match animation, I get my animation, but no gravity and vice versa. So how do I get both, animation and gravitation? As an additional question: how can I give the vellum object an initial frame; so I can kind of skip the falling down part and start right away with the animation. Thanks in Advance Vellum Test.hip
  9. Hi everyone. I have flower with of which I have isolated the stem and ran it through a simulation. I now want to reattach the head of the flower back to the stem but I obviously want the heads orientation to match with the new simulated stem. I have tried point deform but cannot get it to work. Although it does seems to be close its not matching up. attached is a hip with an isolated simple example of what I am trying to do. Any help is greatly appreciated. Thanks Attach_Flowerhead.hiplc
  10. Vellum strut setup

    Hi everyone. can anyone tell me how to make strut constraints in vellum work with a thin object? Attached is a hip file. Try switching between the thick and the thin tube and you will see that the thin tube collapses while the thick one behaves as one would expect. Thanks odforce_example.hiplc
  11. Wiggling Fur

    Hi all, I created a vellum fur simulation for my chimpanzee that simulates the guides perfectly. But when I render, the actual fur, especially the longer hairs, are wiggling like crazy. It is especially noticeable thanks to the white hairs I have. As far as I know, I have no wind forces activated. I've looked around and tried many different renders with different sim parameters but the same always happens. If anyone could take a look I'd be grateful. I'm attaching the project with some renders so you can see the problem. I deleted things like textures and sim cache to keep the file size smaller, creating the cache is quite quick anyway. If anyone has any questions about the setup just let me know. Thanks in advance ~Tomas
  12. Vellum string constraint break

    Hi everyone, I'm currently having trouble with breaking a vellum string object in half. The idea is to make a saliva strand that's stretching before breaking in the middle. Currently i have a line that's vellum string, attached at the top point via "pin to target" constraint to an animated object. (string constraints are SOP level, fed to DOP node, with "pin to target" constraint done within the sop solver "forces" subnet) Sim follows the object, and i can break the "pin to target" constraint itself via the vellumconstraintproperty node, set to the group with the top point. I tried various ways to group the centre point of the line, and keyframe another vellumconstraintproperty node, but it doesn't work. Can anyone enlighten me on the proper way to break string constraint points in a keyframe-able way instead of just using stretch stress? Thank you very much in advance!
  13. hi, I am testing vellum, and have a question. When testGeo is coming up from ground, all vellum particles are influenced and pushed away. Also, when he hit ground with hummer and lift it up, particles looks being sucked into holes made by hummer. However, these particle reaction should not reach such far away distance. I'd like to know how to control the influence distance. So far, I am thinking of solutions: 1 - reduce constraint iteration, 2 - make a space between particles at emission/creation times. 3 - add more friction, increase particle separate / highres- sim, etc. This result could be ok for sand FX, but when making snow ground, this won't work. Particles should be very rigid, and particle only moves around testGeo's feet and hummer. If anyone knows how to control it properly, let me know thanks!!
  14. Keep uv on deformed mesh by points

    Hello ! I hope that you all are ok ! I have a problem that I do not understand ! I made a point simulation from a geometry so that it deforms with an elastic effect. I want the final result to keep the uv's basic geometry. I have the VDB, it does not work well. The deform point works almost perfectly, indeed after a certain moment of the simulation, it pushes certain point anyhow and the geometry is badly deformed. I would like to know how to properly adjust the deform point, or another technique to perfectly keep uv if needed ! Thank you ! at_vellum_sticky_uv_OD.hiplc
  15. 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
  16. 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
  17. 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
  18. 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.
  19. 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?
  20. 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
  21. 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
  22. 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
  23. 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!
  24. 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
  25. 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
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