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Found 116 results

  1. Hey, I have this big pillow with small balls scattered and glued onto to the big pillow, now i want to inflate and deflate the pillows and drive it via a attribute noise. This works wonderfully in the dopnet when I use the Vellumconstraintproperties with just the balls as source, however if i bring the other vellum source in the dopnetwork (big pillow) and merge them, it seems the parameters get overwritten by the second vellumsource and so my inflation/deflation doesnt work anymore and many weird things start happening. I feel like im nearly finished with my setup but just get one little thing not right which lost me already several hours, does someobody has a solution to this? I´ve attached a file, sorry for the mess but problem is hopefully just solveable in the dopnetwork. ODFORCE_2XCONSTRAINTPROPERTIES.hipnc
  2. I was trying to make mixed constraint, but it doesn't work... If i bypass 'glue constraint relationship' node, it works and i have no idea to fix this.... pls help
  3. Hi, In this documentation, there is a phrase of The Vellum Constraints node now has options to adjust the size of the cloth automatically. I'm using H19, same as the documentation, but I don't see such options in my vellum constraints. Is there a way to make it visible?
  4. Hi ! I'm currently struggling on breaking constraints. I want my constraints to break if their length is higher than a given threshold. These constraints has to be soft constraints and I have to keep them animated (it's for my work). I tried to break them in the SOP Solver connected to the constraintNetwork, but for a reason it doesn't work at all. I've created hip file to show the problem more clearly. If you dive into the SOP Solver node you'll see that, long constraints get detected, but it doesn't affect the simulation. Break_Animated_Cst.hipnc
  5. Hi I just want to confirm if my understanding is correct. Basically in a simply scene like this. Two object hard constraint together with two anchors in between. When constraint_type = "position", only one anchor should rotate. Simply because only two object involved, if they are constraint by one line, they should rotation around one point. If we want to achieve effect of box rotate around two anchors, there has to be a third object in between. Otherwise there will only be one anchor rotate. The other one will never rotate in constraint_type = "position" mode. I'm not sure my understanding is correct, can someone confirm this? Thank you.
  6. Hi I been playing houdini constraint recently. I find the behaver of bullet hard constraint is not very easy to predict, especially combined with condof, condir, position, rotation and angular motor. I have an simple file as an example. One box hard constraint to world space. Using one wrangle node with s@constraint_typle = "all". it works as expected. Box stay there. When I split constraint with position and rotation. Give them all condof = 3. Ideally it should be act same as the last one stay there (I assume), but box start to fall. I tried constraint force mixing and error reduction parameter it can improve but I'm not sure I should do that since this is super simple setup shouldn't use too much tweak. File:hard_constratin_question.hip I'm working on pretty complicate rigid constraint setup I need to fully understand the bullet constraint behaver. Really appreciate the help. I also want to ask is rbd constraint the better way for complicated rigid body constraint with lots gear and mechanical parts and vellums. Thanks
  7. I have a character rigged with shoulder and waist vellum constraints to keep his clothing in place for animation. I'm trying to use a third constraint for his lapels, but I want to break it or turn it off at a certain point in the animation. I've watched Rohan Dalvi's H17 video on how to use a Vellum Constraint Properties node to animate the Break Threshold value, and that works well, but it breaks *all* of the constraints in the vellum setup. I'd like to just break the lapel constraint. Is there a simple way to have the Vellum Constraint Properties node work only on that one lapel constraint? Thank you!
  8. hi, in houdini when ever i add grain and add some constraints between them (glue constraint ) i face problem that the grains rise up in Y axis infinetly. and to fix it i increase mass in those glue constraints by 8888888 mass which became too heavy on cloth, is there any solution or i missed up something. but when i take them in dop it works fine no issue.
  9. Hi all, I've looked - but I can't figure out how to pin a hand in Houdini using Kinefx. I've got two situations: -My input motion capture has a person holding a mobile phone with both hands - I need to pin one of the hands to the other hand as they walk around so it looks like both hands are properly holding the phone. -Also some of my motion capture has a bad arm that twitches erratically at times. I'd like to pin the hand of that arm at those times and bypass the twitch. Does anyone have a suggestion of how to go about this. Or point me to where there's good info on this. Coming from Nuance, Motionbuilder, and Maya, what I'm looking for is referred to as pinning (or 'hand/foot constraint pinning') Can't find anything here in Houdini around those terms. -Sim
  10. How to rotate constraints

    Hopefully this clip explains the problem: 2 packed geos are hard constrained together, tube animation (translate and rotate) is transferred from SOPs. The constraint works for position but rotation, how to make sure the constraint network understands there is rotation? Desired behaviour: Scene file: 001.hip desired.webm current.webm
  11. Hello, i have a question about RBD ragdoll simulation. I have two simple agents that consists of three cylinders each. Is it possible to connect sepparate ragdoll collision shapes with additional constraint? Let's say with a fixed line that would bind them together? Thanks in advance!
  12. Hi, I'm searching for a way to apply some motion to a camera that already have a constraint. Just to clarify, my camera have a lookat constraint and I want to apply a "camera shake" after the lookat. I tried to use a noise and add it to my rotation xyz, and it to get applied, but due to the lookat happening just after, it doesn't do anything. Is there a thing that I'm missing or is it just impossible to combine both (wich seams weird to me) and I should animate my camera and recreate the "lookat" effect by hand just so I can apply my noise ? I hope that I'm understandable enough Here is my project setup, The camera is the SCENE_1_Cam_1 with the constraint in it and the noise is in the "motionfx" CHOP Network, in the network box also named "SCENE_1_Cam_1" Animatic.hiplc
  13. Why Bullet sucks at Car rig?

    Why difficult to the constraint when using Bullet Solver. I tested in C4D's Bullet Solver. it was superfast to rig dynamic car. The result was Impressive. In Houdini, Standart RBD Solver was easy to constraint. In my mind, I want to Crash many cars in my scene only use a bullet solver. Any Pro guys, Can you do in Houdini? Thank you. Here is how I ***** up the scene. Car_Crash_v001.hip
  14. Hello, In the attached file I am using 'vellumconstraintproperty' in the solver to break the Pin Points constraint at frame 100. There are 20 strands that fall away as expected. Ideally, I would like to break every point of the constraint individually, so I can have one strand fall away every 5 seconds for example. I've tried a number of different techniques and videos but can't solve this problem yet. Maybe each point can be referenced in Vex in the solver somehow? Any suggestions are much appreciated. Thanks. strands.hiplc
  15. Hello, I have a scene where I am emitting circles, where a POP wind is creating the noise, but I want to be able to limit it only on the Z and X axis. How would I be able to achieve this?
  16. Hi! Im trying to update the stiffnes of my pin to target constraint inside of a vellum contraint property , but when it updates it doesnt updates with the paint attibute im using to scale by the stiffness. Is there a way to do this inside the vex option on the vellum constraint property?
  17. Hello everyone ! In order to model a ceiling mobile (such as the ones in a baby's bedroom), I dived in the depth of wire objects, and I feel like it is much less intuitive than the usual DOP workflow. What I want to do is to tie certain objects (in my case, that would be origami birds modelled with the help of the amazing entagma tutorial from last week) to wires, which are tied to a static wooden part. The part where I'm having issues is when it comes to tying together the solid objects (which come as a RBD packed object) to the wires. I've tried several methods, all of which have failed me for now. 1. I tried using the SBD pin constraint from the Wire shelf. It kind of works, but I still find it very hard to control, and it is impossible to simulate the physical behaviour of the whole system (I have to simulate the RBD packed objects separately, and tie the wires afterwards). 2. I tried the more classical RBD approach, using constraint networks. This is the approach I would prefer, since it allows me to simulate the full system. I have set up the constraints using a Connect Adjacent Pieces SOP, which I modified a bit to add the anchor_id attribute on the constraint points. All of my pieces, whether it be the RBD packed object or the wires, come as separate objects with their own unique names matching the name specified in the constraint points. However, when I play the simulation, the constraints do not tie the objects to the wires, and the wires go wild while the RBD packed objects fall due to gravity. 3. I've started looking at Vellum and other cloth simulations, but I'm very new to it and it doesn't seem to integrate very well to RBD workflow which I'm used to. I've attached a hda with my project file, where I've replaced the bird objects with polygon spheres for simplicity. (It still doesn't work when I play it on my computer) If anyone has the time to take a look at it and tell me what I'm doing wrong or put me on another track, I'd be super grateful ! All the best, Nolan Constraint_Wires.hdanc
  18. Hello, the problem is, in the example file named "GravitySlideExample", this box only rotates along the x axis (red) given angle. BUT, I want it to rotate along y axis (green) without changing slider way. This is so important for making really easy and stable car dynamic rig. Is it impossible? https://www.sidefx.com/docs/houdini16.5/examples/nodes/dop/rbdsliderconstraint/GravitySlideExample.html
  19. Hey I'm stuck with something minor. I tried to create a simple popping balloon in vellum. If I use the edgefracture with a fracture curve (1 piece) it works just fine. If i try to use the "Initial Pieces" in the edgefracture sop it seems the whole thing breaks. Any idea what I could do to fix this? balloon_01.hipnc
  20. Hello all! I have been trying to figure out how to dynamically update the constraints in a vellum constraints property node based off of the distance of the vellum object from a given point in space, but I cant figure out how to make this calculation dynamically in this context. I can measure the distance before and after the vellum solver with a distance node but they only give me static values in the solver context so I dont know how far things are once theyve moved. Havent been able to get xyzdist to work either. Any help would be greatly appreciated as this project is very important to me!!
  21. Hello, question is simple but I couldnt figure out how to solve this. I am trying to make car suspansion mesh. The meshes that are bottom are connected to the wheel. Above meshes are gonna be suspension mesh. I connected them with "connect adjacent pieces" In my dopnet, I have "constraint network" with "slider constraint relationship" But unfortunately, slide axis is depend on world axis, not constraint axis. It makes me sad HOW HOUDINI does not have option that I can use constraint axis... Because of that, when I rotate car, that 4 constraints move too, but in Dop net, slide way isnt change. See the image bellow: SO, this issue is not just for slide constraint, same with cone twist axis too. There are two way to fix this; 1. option is, I am not gonna change position&rotation of my object in sub network (which is car). BUT How can I change it in DOP network? There is no "translate node" in Dop. (There is "position" node but it doesnt work like "translate" node) 2. Option is, "slider constrait relationship" node must have my constraint axis data. How can I do that? I have thousands of problems, this is just one of them.. THANKS !!
  22. Hello, I would like my drapped cloth to be a bit more pulled towards the bottom when I am simulating and not have it fly upwards too much. see screenshot. I just want the shape to stay a bit more consistent. I know that the arms are pulling the cloth up at some point, but I am sure I can cheat my way out of this!!! I created a @massgradient with a wrangle using the bounding box of my cloth. This feed into my vellumcloth>vellumDrape>DOPnet. So this attribute should be 1 at the bottom and near 0 at the top. How can I multiply mass by this attribute in the DOP? Is this even how I should do this? I tried using a Pop Property inside DOP, setting mass to 10, and in the VEXpression, typing @mass*=@massgradient; But this doesn't seem to do anything, and when I bump the mass to 100, it gets really weird and doesn't do what I would imagine. Any Ideas? If the cloth had a lower resolution, I wouldn't have this problem, but I want to keep this wrinkled look. Thank you very much
  23. Wire constraint network Question

    Hi all- Building a procedural constraint network for wires by connecting the interior points in a grid. It works fine for some grid dimensions, but not others, where the sim blows up. shown below a 5x5 and a 6x6 grid. A 15x15 grid will work fine, but a 6x6 one won't. Curious! I'm building zero-length constraints from the interior points and setting the anchor points as follows: int wirepts[] = nearpoints(1,@P,.0001); foreach (int wpt; wirepts) { if(wpt != wirepts[0]) { int pt1 = addpoint(0,v@P); int pt2 = addpoint(0,v@P); setpointattrib(0,"anchor_id",pt1,wirepts[0]); setpointattrib(0,"anchor_id",pt2,wpt); int newprim = addprim(0,"polyline",pt1,pt2); setprimattrib(0,"constraint_name",newprim, "WireGlue"); setprimattrib(0,"constraint_type",newprim, "position"); } } setpointgroup(0,"delete",@ptnum,1,"set"); I delete the original points later - I'm not using the first of the nearpoints to avoid a prim with the same anchor points, I thought that might be the problem, but it didn't seem to matter. Does anybody know the reason why this happens? Am I missing something? Thanks - I'm including a sample file. wireGridConstraints.hiplc
  24. If you look at the attached ColIgnoreA.mp4, you can see the "red" and "green" collisiongroup attributes ignoring one another. Results are as expected. In ColIgnoreB.mp4, with those same collision ignore groups, I glue one red and one green sphere together. The free red sphere now collides with the green sphere, which is not as expected. The best I can tell is that when these pieces are glued together, they somehow combine their collision groups. When I set collisionignore as "red green" it ignores them both. However I still want red to collide with red, so it does not work for me. What's more is that Soft and Hard constraints work as expected, ignoring green sphere collision. Only Glue is strange like this. Is there a way around this? ColIgnoreA.mp4 ColIgnoreB.mp4
  25. trying to hang a body on a rope

    Hi, I'm trying to hang a body on a rope. For now, I'm doing it using hard constraints. The main shape is fractured by Voronoi fracture and all the pieces are connected with hard constraints. The rope attached to it is just a set of spheres connected with hard constraints. So far, I don't like the results. The rope looks unnatural, way too springy and I don't know how to fix it. My questions are: 1. Can I somehow influence the behavior of hard constraints to eliminate springiness? 2. Maybe I should use a different pipeline altogether?
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