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About haveahapyday

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    Michael Shoppell
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  1. Greetings all, I'm working on a shot where I have a spinning falling cloth. In order to control it I have the center of the Vellum cloth attach to an animated object. It was working fine for a while, but somewhere when I iterated my .hip file up, the constraints started to be generated off center. I tried to match the settings from the previous correct one and even copied the properly functioning nodes over, but it was still misbehaving. I attached a photo of what it should look like vs what's going wrong. Even stranger is that in the attached .hips, there's a rogue switch node that if I delete it, the constraints won't form at all. It happens in both the correct and wrong versions. The switch node isn't even connected to anything in the stream of data as far as I can discern. The .hips are reduced from the larger shot I'm working on and the switch is a leftover from removing the collision geo after a certain point. For the moment I'm going to back step to the working .hip, but I was wondering if I'm missing a setting or this is just a bug. I have a hunch this might be an issue with using Vellum in a SOP context, but I'm not certain. Using Houdini Apprentice 17.0.352 on Windows 10. Thanks! haveahapyday_vellumConstraintIssue-correct.hipnc haveahapyday_vellumConstraintIssue-wrong.hipnc
  2. [SOLVED] Is there a way to animate Vellum constraint properties?

    Thanks for pointing that out, I don't think I would have picked that up. I'm just glad they put this sick solver in, I can wait for further improvements.
  3. [SOLVED] Is there a way to animate Vellum constraint properties?

    I did use a null initially which is probably faster, but I thought it might make a little more sense if I had to go back to it later. Six one way, half dozen the other? Or is there more to it? oh wow, i love the little detail created when the ball is rolling but not sticking. if i understand this correctly, this version works because both the floor and sphere are Vellum cloth opposed to the sphere being an RBD/whatever Vellum uses for default collisions? haha that shaolin test is hilarious. great implementation. thanks for sharing.
  4. [SOLVED] Is there a way to animate Vellum constraint properties?

    Yes! This is exactly what I needed! I saw you could dive into the SOP Vellum solver, but wasn't certain what you were supposed to do in there. It seems to me at the moment that the SOP level Vellum nodes are kind of like an all or nothing deal, but I could be wrong. In the future I think I'll go the DOP route, but right now I just want this shot done, haha. I found a work around to prevent it from sticking immediately using a delete and switch SOP. If the collision geo input is empty until you need it, the attach to geo constraint won't trigger. Hooking up the switch to the geo attach activation parameter to make things a little less cumbersome. vu_vellumsticky_SOP-haveahapydayEdit.hipnc
  5. Greetings! I'm working on a shot where I'm using a sphere to push a cloth through a hole in another object. Up to a point, the sphere acting as a collision object works great. However, the cloth slips off the sphere halfway through the sim. I was hoping I could animate an "Attach to Geometry" Vellum constraint to ensure the cloth sticks to the sphere after a certain period of time. I can't seem to figure out how to animate any constraint properties though. I'm doing it at the sop level using Houdini Apprentice 17.0.352, if that makes a difference. I tried making a simple scene with a grid and sphere through vellum constraints. The idea was to let the grid fall to the ground and animate the stiffness value on an "Attach to Geometry" to pick it back off the ground, but it doesn't work. I also tried the "Attach Frame" setting on the "Attach to Geometry" constraint, but that doesn't seem to do the trick either. Are Vellum properties set at the beginning of the sim and unable to be changed? Or is there some secret sauce I need to add? Do I need to do this in a DOP network or change values upstream in a wrangle? I can't seem to find anything but beginner Vellum materials online at the moment. Thanks! haveahapyday_vellum_animatedPropertiesTest.hipnc haveahapyday_vellum_clothHole.hipnc EDIT: Solved! Check Noobini's responses in this thread.
  6. [noob vex] how to access single component of matrix3?

    whoops, was confusing the example i wrote up with what i was actually using. edited the original post to make the example accurate. i was using H16 at home when i was trying that so maybe that could be the issue? getcomp() works in V17, but float testValA = testMatrix[0][0]; throws this error: "Call to undefined array index operator 'matrix3[int]', returning one of vector4, vector2, vector, float[], int[], vector4[] or vector[]."
  7. correct me if i shouldn't be doing things this way, but basically in a wrangle sop rather than creating a bunch of separate control channels, i want to make one matrix3 and then access the individual components. here's a couple ways i've tried: matrix3 testMatrix = ch3("testMatrix"); f@testValA = testMatrix[0][0]; f@testValB = getcomp(testMatrix, 0, 0); f@testValC = testMatrix[0:0]; i apologize if this is beyond n00b, but i've tried over an hour to figure this out and got no where. thanks!
  8. Art Directing Falling Cloth Tips/Techniques

    found a good method to solve this. i ended up making two separate sims and then used lerp() in a pointwrangle to interpret between the two.
  9. greetings! i've been tasked with creating a falling handkerchief that lands on a head, completely covering the face. it's 85% of the way there, but the last 15% is eluding me. found a few good resources here on odforce and the net, but now i find myself in a "guess drop position + resim" loop. i haven't done much cloth before, so i'm not certain if that is what it comes down to in some situations. i'm looking for any techniques to direct how the cloth falls and ensure it lands on the face. brief summary of what i've tried: - if i position the cloth geo above the head, landing the cloth on the face is easy enough. however, then it's just a boring, flat square falling until it deforms with the face. - to add detail while falling, i created a constraint that pinches and spins the corners together before dropping. i like the details it creates, but find the pinching turns the cloth into a shuttlecock. when the cloth contacts the head it doesn't unfurl nicely, just kind of hits and slides off. - turned the pinch constraint off and used a vortex force to generate spin on the falling cloth. definitely a step in the right direction, good detail and motion. the issue now is i don't know how to land the cloth without guessing at an initial drop position and constantly resimming. - made an attempt at using a pre-sim'd cloth as the embedding/rest/target geo in the cloth object node. no progress there, although i'm not sure if i'm using those settings properly. if there are any fabric wizards out there, i'd eternally appreciate any wisdom on how to add natural motion to a falling cloth and still have it land in a specific location. thanks! handkerchiefFace_haveahapyday.zip