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Found 61 results

  1. Hey all, I've tried searching the forum and the internet at large, but couldn't find an answer to this. Apologies if it has been asked before. I'm trying to create a constant stream of constrained vellum grains. Continuous emission with Vellum constraints (each frame/step) just explodes, and adding the constraints through a SOP solver made Houdini unstable.. Does anyone have any idea how to go about doing this? I'd appreciate any tips you could share. Please see a simple scene with the issue. Thanks! vellumConStream.hipnc
  2. [SOLVED] In/Active Constraints

    I'm trying to shoot a cannonball through a small castle. The cannonball animates and blasts through the walls, but the constraints look like they're being ignored (or they aren't hooked up properly), so the entire structure collapses the moment the sim begins. The clusters are being ignored as well, but I can't figure out why. Many thanks for you even reading this. v17.5 rookDestruction_chazS.hipnc
  3. Hi everyone, Currently i'm running into an issue where my constraints aren't breaking. I spend a while on figuring out why it doesn't work and I still don't have a clue what i'm doing wrong. My setup at the moment is that I have one curve with 3 constraints 1 hard constraint to keep the wire in place. 1 spring constraint that is pulling the wire down (This is a placeholder for collisions later on. It's just there to apply a force for testing). 1 spring constraint without a strength to measure the angle between the tip and a point somewhere on the curve The thing is, when i put them all in one constraint network and break them based on the angle, nothing happens and i couldn't figure out why. But when i put the spring constraint that is pulling the curve, into another network the breaking works! Is there anybody who can explain why this is happening? Why wouldn't it break with all the constraints in 1 network? Is it because i pinned one of the points of that constraint to a wold position instead of a point on the simulation geometry? That's the only thing i can think if that is different than the other constraints. Thanks! break_constraint.hipnc
  4. 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
  5. Hi There, I am trying to set up a initial state for a grains sim(that has constraints). I saw those two tutorials about people having similar problem: https://lesterbanks.com/2018/03/initial-state-houdini-simulations/ [lesterbanks.com] https://forums.odforce.net/topic/21727-set-initial-state/ [forums.odforce.net] It seems like that method works for grains/particles that are with out the constraints though…. Has anyone idea how I can solve that ? Thanks a lot for help! Grains_Initial_State_Test_v01.hiplc
  6. Animated colliding objects

    I have a project coming up that will require me to hand animate objects but get them to collide with one another. I'm an experienced Houdini user but setting up DOP simulations has never been my strength. I've attached a hip file with the basic situation here: moving_furniture.hip Furniture will be sliding around, probably animated by hand. The objects need to bump into one another and react naturally while doing their best to follow the target animation. I had assumed that this would be some sort of combination of RBD objects, proxy Geo & pin constraints, but I've been unable to understand how to wire it up. There are so many great examples using this sort of thing but nothing that really explains how to combine following constraints that are animated in world space. Thanks so much
  7. 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!
  8. 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
  9. Multiple Constraints on One Object

    I was wondering if anyone has had experience having multiple constraints on the same object and breaking them apart separately. the effect I'm aiming for is to have a some large rocks be ripped of a section of rubble and while in the air start to break apart into smaller pieces. I've tried setting up my constraints based on the groups created from the Voronoi fracture and sub fracture nodes, however this causes problem when trying to disable the constraints in different areas. Any ideas? ConstraintsHelp.hipnc NewRubble.abc
  10. 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!
  11. Breaking constraints

    Hello guys I'm doing some testing on breaking constraints, for now, I was only breaking constraints based on angle, force, torque and using a slider for adjusting values. Do you guys have any techniques to share for breaking constraints, what kind of rules can be used?
  12. Hi, I'm trying to wrap my head around why this simple set up isn't working as desired. Inside of an SOP solver, I look for the first and last points on a curve and assign them to groups. I then try and assign these groups in the Stitch constraints on a multi-solver but they aren't taking effect. Can someone point me in the right direction? I know this is simple in SOPS level but I'd like to expand upon this in DOPs and make the Stitch points animate-able. Thank you constraint_simple_01.hiplc
  13. 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
  14. Hello, is there any analogue of grains attribute "attractionweight" when using vellum solver? Or maybe some advice to achieve the same result?
  15. Can't select points in DOPnet

    I have a question that is so dumb that I can't find an answer in Google. I'm working with FEM objects. I need to select points in the DOPnet to make constraints. I can't select points, just objects. Thus: can't do pinning and stick things to things. I've done this a million times on my home computer, but I'm using a different one now (with H17 installed mere days ago), so I'm sure it's some big obvious setting. Thanks and duh.
  16. Hey there, I'm doing some RND on destroying a building with a force. And I'm wondering what's the best way of using constraints. Is glue used with minimal strength just for holding geo together and then using cone/hard constraints? And what about constraints between clusters? I believe the strength between clusters must be low and for the clusters really high, but do I have to use also cone over cluster constraints? Are cluster constraints even necessary if you use cone/hard? I'm just confused and can't decide how to use constraints properly. I would really appreciate if you guys can give me some tips on that.
  17. Hello I looked at F1 and still could not figure out how to make this connection between objects. RBD Material Fracture has its own constraint system and in this way is not done, but to connect different fractures, such as the image example, you need to use Connect Adjacent Pieces, but I could not get Constraint Network to identify this constraint between the objects. I used the old method to paste as pieces and can not make the two examples dialog
  18. Vellum animated constraints

    Has anyone had any luck breaking constraints in vellum with animated attributes? I have set up a simple scene the constraint breaks fine using a non animated attribute but if you go outside the dop and plug the BREAK null into the animated colour the constraint fails to break, I've tried breaking it with some simple vex and had a play around with the vellumconstraintproperty node to but not having much luck. on a side note has anyone been having a problems with the new visualizer tools in 17? should be able to click on a attribute in info tab and it will show the attribute in the view-port, seems to be throwing a error. Thanks. string_release.hip
  19. hello! is there way to get back animated constraint geometry from dop network ? i mean i`d like to have the same gometry that i see at dopnet that shows constraintnetwork node when 'show guide geometry' is on
  20. Hello Odforce! I'm trying to setup a simple earthquake scene. This is where I'm at currently. gif I've modeled and fractured a simple wall that I am trying to add into the scene. Currently there are animated boxes that are constrained to chucks of the ground, and wood. When I add the wall pieces into the constraint network everything breaks and the ground doesnt follow the animated geo. I don't really understand is happening, and I would appreciate any insights! I've attached the scene file if anyone wants to take a look. Thanks in advance! please_help.hipnc
  21. Hey everyone, I'm happy to introduce Bullet Breaker Core, a toolkit for easy animation of bullet simulations. Link to Bullet Breaker toolkit -> gum.co/hTnq The purpose of Bullet Breaker is to allow for easy animation control of fracturing objects inside of Bullet simulations in Houdini. Bullet Breaker Core comes with digital assets to allow for ease of use in setting up and visualizing Bullet Breaker attributes. Bullet Breaker Core also comes with a brief tutorial which goes over how to setup bullet breaker compatible fracture geometries. Bullet Breaker Core does not use Houdini constraints and while it is possible to use Bullet Breaker with Houdini Constraints it is not meant to be used with Houdini constraints. Includes the demo scene file and all digital assets! Hope people find this toolkit useful! You can reach me at trzankofx@gmail.com for questions or comments.
  22. RBD glue constraint problems

    Hello all, I'm trying to learn through RBD by doing a sim where a fence gets riddled with bullets. I have the basic sim in place and where I think it all should be but when I sim it just explodes anyway instead of holding together. Attached below is the scene file because I'm truly lost. Thanks! FenceBreak_01.hipnc
  23. destroying animated geo

    hello, i am currently doing some r&d for a bigger project in which i have to destroy certain parts of a transforming building. so i started to animate a building-like shape with a growing collider inside, so I could start researching how to fracture and constraint animated geo and destroy just the parts that really get hit by a collider while the rest follows the animation. it worked out quite good, but now i got to the problem that even if the destroyed pieces are laying on the ground, they still sort of follow the overall animation. I tried to put deforming to 0 in a sop solver inside dops after reaching a certain speed but that didnt really help at all.. can some of you give me any advise? thanks in advance! animFracTest.hip
  24. In an RBD simulation I want to use both glue constraints as well as the i@active attribute to time my destruction, but seems like the two can't work together. Has anyone come across that before and has a solution? I have an example file that illustrates the problem. thanks georgios rbdContraintsActive.hip
  25. Wood Destruction - Cone Twist

    Hello odforce! So I'm having my first go with the cone twist constraints to simulate wood breaking, I researched around and it seems they are the best way to achieve the "bend before break" effect seen in wood. So I've got a pretty decent setup so far, the planks are connected w/the cone twist constraint, the posts have a regular glue, and there's an overall glue to keep everything together. The only issue is this Y-axis bendiness the planks seem to have as if they're sushi mattes! (The one that falls closest to camera is the most obvious) I've tried adjusting Max Up, Out and Twist, but can't seem to find a balance between the planks not responding to the force of the ball, or bending all over. I'd appreciate any tips to help keep the planks stiff while still bending from the force, or just in general to help improve this sim! Thanks in advance for reading.
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