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Found 114 results

  1. 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
  2. Hi, all...need to do a shatter effect where the outer 'shell' of a static (for now) character/figure crumbles to reveal a different material/surface beneath. Been doing a lot of testing with a simple torus as it's a fair representation of the tubular topography of most of the figure (arms, legs, torso, etc). I feel I've finally got a good grasp on all the fracturing basics, but for the life of me I can't keep the outer shell fragments from interpenetrating with the underlying shell. I've tried: Increasing the DOP network substeps Increasing the rigid body solver substeps Switching the RBD packed object geo representation from Convex to Concave Altering the collision padding based on what it does to the guide geometry Increasing the number of fragments in connection with all of the above The changes either lead to little difference or in cases where I kick up the substeps and subsequently (I think) the precision, the fragments do the old-style 'exploding off the surface' thing. At this point, I have to wonder...in this situation should I just switch to the RBD solver? I'm okay getting hammered on sim time if I know it's going to work in the end. Oh, and a question about the collision padding...is that designed to pad the fragment intersection with other surfaces, each other, or both? Any help would be great. Really been banging my head against the wall on this one. -- moltenCrazy Shatter Tests - Torus - 02.hiplc
  3. 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
  4. Hello, I'm starting to learn Houdini and following a course from PluralSight named Architectural Destruction, the final result is pretty much the same I need in my project, an exploding building with many different layers and materials. All the previous steps worked like a charm, however when I try to break one part of the building using a force I created, it behaves different from the tutorial, even configuring the constraints. Instead of exploding the area, like in the tutorial, it looks to blow the entire building at once, indepedent of the size or magnitude of the force, as the example below: Generating the force I have an attribVOP configured this way: And inside the DOPnet I have a geometryVOP this way: I tried to change the constants to reach the result, but with no success at all, is there any way to create some kind of falloff or decay for the force? How can I proceed? Any hints or ideas of what is going on? Thank you very much! Any kind of help is very appreciated !
  5. Hi all, I'm trying to create some physically accurate bullet sims using real world values for mass/density and friction, so I've been looking at some engineering tables for friction coefficients: http://roymech.co.uk/Useful_Tables/Tribology/co_of_frict.htm What I'm confused about is this: It seems that real world friction is calculated based on the coefficient of friction between two objects, eg wood & wood has a friction coeff of 0.25 - 0.5; wood and concrete 0.62; wood and metal 0.2 - 0.6. So friction is not a material specific attribute, so if I have 3 houdini objects, one wood, one concrete and one metal, how do I create realistic friction settings for each combination when I can only set a single friction value per object? Is it even possible? Also, how does Houdini calculate friction coefficient between two objects? Does it multiply the friction values? Or average them? Any help is much appreciated Thanks in advance!
  6. Hi all! I'm doing a rope sim with wire solver. And I wanna interact wire with RBD sim. I did each sim at the same time in the same DOP network. But it was not doing well. problems are... 1.Why the wire goes through the cube? 2.Why the cube breaks before the wire hits? Any solutions? Thanks. WireBullet_test.hip
  7. glue constraint issue

    hey !! why i'm getting this weird glue constraint issue the obj gets hit the glue broken then it gets attached again . thanks
  8. Hi, I have a case where I have, lets say an object which comes from bulelt sim, with v and w. Based on that object, I want to drive another bullet sim, updating v and w, so the rest would be calculated by bulllet sim. In the scene I attached it works pretty much, except it flips at some point. I understand that there should be some catches on quaternions. I suppose, there should be some sort of angle check and etc, but can't make it work... update_angularv.hip
  9. Duplo Bear via Bullet Constraints

    Here is a breakdown of how I made this bear made out of duplo blocks: The video isn't super comprehensive, I mainly cover setting up the constraints in SOPs, though I briefly touch on some other parts too. But the hip file is available to pick apart! Thanks! duplo_bear.zip
  10. Hi, I'm trying to achieve a particular effect which I though would be relatively simple (see attached image.) I have a shot I'm working on where I have a mechanical heart and I want a bullet to go straight through it without losing impact, shattering the heart as it goes. I have pre-fractured the heart geometry with voronoi and used glue to anchor it in place. I then did a simple RBD sim as you normally would when fracturing objects. However, when I used a sphere as a placeholder bullet with initial velocity, it just bounces off the heart. Even when I increase the mass of the 'bullet' it still bounces off. My question is, how would you approach this? I'm completely lost. Cheers!
  11. Bullet and Flips collisions?

    Hi, Can someone please help me confirm is bullet is compatible or not with flip simulations? I set up a simple packed geo as a static object for a flip simulation. The geometry collision is properly calculated as convex hulls… (image1) But as soon as I run the sim this weird shape appears (image2) It is like if the flip sim automatically converts the collision geo into a weird resampled volume. is this true? Would this mean that the flip solver will automatically convert the packed geo into a volume? Feel free to look at my set up… I simplified the scene to run a test. (the hip file is attached at the bottom) bulletandFlip.hiplc I also added this post in SideFx forums as is driving me crazy trying to figure the solution... I have figured a work around transforming my collision geo into volumes and then just using regular static solver but I would like to have a clear answer about what is going on here...
  12. Hi, I want to emit alot of coins which will be pushed outwards the earlier borned coins Like a growing stack of coins. What is a good way to do this? Cause What bullet now is doing is leaving all the intersecting geometry Alone (no popping)
  13. Hi all! I'm currently trying to find a way that I can control when an attribute on packedrbdprims coming into DOP's gets written to from the "Overwrite Attribute from SOP" box and when it gets written to from the bullet sim I have set up. I have a set of packed primitives with rotation animation on them being fed into a bullet simulation, I'm also adding an "active" custom attribute which is being used by a SOP slover in DOP's with a vex wrangle inside it to activate them when the value equals one. What I also want to happen is have the orient attribute on each packedprim update from the existing vaules from SOP's right up until the point when the bullet solver takes over and begins writing to the orient value. I know that I can add orient to the "Overwrite Attribute from SOP" box but what I 'm hoping for is a way to disable this function for each object as they become active rigid bodies, essentially adding to the orient values that exist on that particular frame and continuing with the sims values. Instead of having the sim take the orient values that exist at the first frame or continually updating those values as the packedrigidbodys are influenced by the sim. I know its poor form but I'm afraid I dont have the project file on hand to upload, sorry guys :S hopefully I can upload it next week if anyone needs to see it. Any help would be massively appricated! Many thanks
  14. Cloth/FEM and RBD/Bullet interaction

    Hi I've been searching the forum on this topic but didn't find much. Is there a way to get a somewhat correct collision behavior between the cloth solver and the RBD solver running parallel in the same DOP network? I've a bunch of cardboard boxes that's suppose to stack on each other. I'd an idea that the cloth boxes that had come to rest would switch over to be a RBD objects instead, to optimize the sim. But first I got to get the solvers to interact. Any ideas? A simple test scene with the setup is attached (without the switching stuff). Thanks / John Edit: Ops double post :/
  15. Hi all, I am trying some simple tests in dops using the bullet solver. I have hit a few stumbling blocks and would appreciate any input from you friendly people What I'm trying to do: I am trying to get a scene showing a pillar being picked up by a crane (like the ones in fairgrounds where you can use it to grab soft toys), the base of the pillar stays where it is and the rest of it gets picked up by the crane. As the pillar is picked up, the lower part of whats left is crumbling away as the whole thing moves. The setup: Because this will eventually be put into a game engine, I have to keep the number of fractured pieces down, so I split the pillar (Top, Bottom), and then I split the Top even further to isolate the "destructible" area. I fracture this area and animate both objects to be moving with the crane (transform sop within the SOP level) I then bring these objects into a dop network as RBD packedobjects but I can't seem to bring in the animation that is attributed to them. I change the "Initial Object Type" to all the the available selections int he dropdown, including Create animated static objects" but this doesn't seem to do anything. I do know you can do this on an RBD fractured object using the Use Deforming Geometry checkbox, but I'd prefer to work with packed geometry to reduce simulation times. Ideally, I would want the destructible area to just be parented to the Top of the pillar and then I can make it crumble by breaking the constraints. But I can't seem to do that either. In 3DS Max, in PhysX, there is an option to tag objects as "Kinetic" and then choose which frame to make them "Dynamic". That's a very rigid way of working and I'm certain there is a much more flexible way to do it in Houdini but I am still a beginner, especially when it comes to rigid body simulations. So to summarise, the questions I am left with are: How can you bring in animation on an RBD packed object? What would be the best way to achieve what I am trying to do? Thanks
  16. Impact Data from Particular Object Id

    Hello guys, How can i use impact data when an object hits a particular object in my case a ground plane to break the constraints, For eg - i have certain glued objects falling on the ground , some of them are breaking in the air while they release due to impact generated while i want they should only break once they collide with the ground plane else their strength should remain -1. So how could i extract object id of ground and use that as an impact data.
  17. I'm looking to transform one shape of packed RBD's into another. I've looked at the forum and a few of the examples. Specially the lego car which is awesome but they all tend to transform the same set of Packed RBD's from a rest shape to complete form. I am looking to transform from one shape of object to another shape of object. this is a pure Position and Rotation transformation and I think I'm just not understanding the way rotate work to show this I've made a simple houdini file. Any Help to better understand this would be appreciated.
  18. I'm looking to transform one shape of packed RBD's into another. I've looked at the forum and a few of the examples. Specially the lego car which is awesome but they all tend to transform the same set of Packed RBD's from a rest shape to complete form. I am looking to transform from one shape of object to another shape of object. this is a pure Position and Rotation transformation and I think I'm just not understanding the way rotate work to show this I've made a simple houdini file. Any Help to better understand this would be appreciated.
  19. I'm looking to transform one shape of packed RBD's into another. I've looked at the forum and a few of the examples. Specially the lego car which is awesome but they all tend to transform the same set of Packed RBD's from a rest shape to complete form. I am looking to transform from one shape of object to another shape of object. this is a pure Position and Rotation transformation and I think I'm just not understanding the way rotate work to show this I've made a simple houdini file. Any Help to better understand this would be appreciated. packedgeo_shapetoShape.hip
  20. Multiple Solver Interactions

    I'm gradually trying to learn various of Houdini's solvers (primarily cloth, pyro, and bullet for now) and I'm slowly getting to grips with how they work individually. What I'm struggling to understand, and also struggling to find good learning resources for, are the ways to create interaction between multiple solvers. I'm interested in setups for one-way interaction (eg. pyro affected by bullet/rbd sims) but even more keen to understand two-way (or more) interactions. For example, how to have cloth and bullet (and perhaps pyro as well) all working mutually in a dynamic simulation, all affecting each other. Can someone point me in the right direction towards learning how to combine different solvers together? Are there generic ways for doing this (in other words combining cloth and bullet would involve the same understanding/setup as combining pyro and cloth), or does every solver/combination have its own idiosyncrasies when trying to combine? I found this video about combining pop and bullet solvers: https://www.sidefx.com/tutorials/combining-solvers-with-a-multi-solver/ I assume a good understanding of the multisolver is key here. But the multisolver doesn't accept the cloth solver as an input, so it seems like there must be more to it than that... Any help much appreciated!
  21. SOP GEO - FIELD FORCE - BULLET

    Hey guys, working on a destruction peice and wanting to take the velocity from my charachter and put it into my bullet sim - So decided to try and use a sop geometry node to bring in the calculated velocity (from a trail and fluid source) - which is working perfect. But my sop force doesnt update each frame, its static - ive tried changing the expression from $T to $F and other things, not sure if its a limitation or if im doing something wrong? i will attatch a file but will be missing the geo but atleast you guys can see the setup Any help would be great! Thanks Destruction_v3_t2.hip
  22. Instance Pack Trouble

    Hi guys , Based on the tutorial Applied Houdini - Rigids II Structure Destruction I'm try same effect , But i have trouble is instance pack , i m use same techniques in this scenes . But i don't know why matrix replace does not work . Hope your help .Thx every body. Please find attached for details
  23. i have managed to create a network of masked gravity force to drive the RBD packed objects but I'm a little confused about how to proceed further. i need to control the moving pieces of geometry more effectively with further forces as well as create debris from the cracks or where it fractures. any direct help (i have attached an example file) or pointing me towards resources where i can learn further would be cordially appreciated. thank you and best regards fracture.avi fracturingGeoMaskingForce.hipnc
  24. Hey guys, Im creating some procedural Sawdust using the copy sop onto a point selection - i want to sim the objects then dropping onto the terrain for placement, but so far have had no success - tried changing collision modes in Bullet but think the main issue is its all connected as such? (have tried convex hull and per connected set of primitves with no luck etc) and cant think of a way using the skills i have to select every peice of geo individually and then make dynamic quickly without doing it manually (which with thousands of peices of geo is not a good idea) Any help or ideas would be great Thanks Chris
  25. Hey guys, Im creating some procedural Sawdust using the copy sop onto a point selection - i want to sim the objects then dropping onto the terrain for placement, but so far have had no success - tried changing collision modes in Bullet but think the main issue is its all connected as such? and cant think of a way using the skills i have to select every peice of geo individually and then make dynamic quickly without doing it manually (which with thousands of peices of geo is not a good idea) Any help or ideas would be great Thanks Chris
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