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Found 490 results

  1. Hi all! I recently made a free public post on my Patreon, a bit of a New Year's gift. In my destruction classes & SideFX conference presentations I've mentioned that I often use geometry grouping to define the clustered sections in my RBD sims. However, it takes a bit of work to create the feedback for-each loops to set that up, so I've finally wrapped it up into a helpful HDA. Demo HIP file included as well. (I also included the HDA in the November 2020 'quick tip' post, but this version fixes a bug in the size-based prioritization, so for patrons that have that version I highly recommend downloading this one instead!) https://www.patreon.com/posts/45769153 https://vimeo.com/496659441 Hope you find this useful, and that you enjoy the new year! :-) ~ Keith
  2. Destruction III - CG Forge

    Check out the full course at https://www.cgforge.com/course/destruction-iii Cheers!
  3. Hello, I have been making several attempts to accomplish something like Matt Taylor's Seeds concept https://youtu.be/vUvEy37LhqE I have tried a couple of approaches including using a multi-solver but no luck. would really appreciate any input that helps! Motion_Graphics_Designs_By_UK_Based_Artist_Matt_Taylor.mp4 Houdini_Vellum_growth.mp4 Spheres_growth_v001.hip vellum_grains_growth_v004.hip Spheres_growth_v002.hip
  4. Hi, I'm quiet new in this big world of Houdini, i need help. The project consists of creating spheres on the points extracted from a pop simulation and then destroying them. The problem I encounter is that when I put the glue on different spheres it seems that it creates the glue on all the broken pieces. It could be the fact that in the assemble node, it considers those points as a single geometry, but I don't know how to divide those points as unique entities and then apply the glue only on the individual spheres and not on all of them as a single object. Thank you in advance for your attention and any help. I attach the file below. Thanks a lot! Fra_pop_copysphere_and_rbd_.hipnc
  5. Hi, this is a basic question but I have spent hours and didn't see the answer anywhere. I have some geo packed and ready for a rigidbody simulation, but i want to cotrol when the geo start to simulate. So I put a wrangle node to control it, for example: I want to start in the third frame: i@active=0; if ($F>3){ i@active=1; } But in the Dopnet, it never starts. In the spreadsheet active keeps 0 and never changes to 1. I tried to put the wrangle in a solver (because it worked for me with working with attribute transfers stuff) but it didn't work either. I did a simple scene with the problem. P.S. I know I can change the frame of the start of the sim but actually i would like to have diferents objects with differents starts so I though @active is the way. Thanks in advance active_update_question.hip
  6. hey all i'm sure this is a fairly simple one but i'm having a hard time with it :/ been at this for 6 hours today so i have a sim of a big wall exploding outward - it looks great but sadly i have a huge chunk of pieces that fly towards cam an i'll be damned if i can find a way around it - is there any force i can apply from the camera that can push them outwards instead of just heading towards the camera and through it? It would be awesome if i can art direct this a bit more! thanks Ant
  7. How to get pyro to effect an rbd

    What is the best way to go about exploding a building with a pyro explosion? Currently I have a setup that has a fractured structure that I add point velocities to and the rbd solver. I want to have a pyro explosion I can use to drive the rbd. How can I do this, none of the tutorials I've seen have pyro. I'm looking for something like this. -
  8. Hi, The problem is getting RBD Bullet pieces to floating properly: Icebreaker_fake_Buoyancy_Bullet_SpinningProblem.mp4 IceBreaker_Ship_PopForce_VexMask.mp4 im running into problem simulated flat sheets of ice being buoyant in a volume. I can get them to rise to the surface with PopFloatByVolume and also a fake popForce with vex using the pieces depth to mask the upward force. The problem is getting them to not spin around the packed bullet point per piece, and instead have proper per point of the mesh have force applied as per proper buoyancy would. So they lie flat once they get to the surface of the water volume! Struggling with the PopFloatByVolume spin settings, and PopSpinByVolume doesnt seem to play ball either. Im trying to go down the setPrimIntrinsic route, where i could blend slowly the rotation to be flatter as they get to near the surface, but im not hitting gold yet and would be great to know if theres a better route. any ideas or approaches would be amazingly appreciated. attached the hip file with where im at. IceBreaker_PopFloatVol_CustomVolumeInput_005.hiplc
  9. Hello everyone, I'm trying to do a multiple explosion effect on a piece of geometry with a glass material and I have some issues with concave shapes. Since the object needs to be transparent I cannot use any kind of pre-fracturing, otherwise it would show. (picture 1 & 2) So I setup a DOP network with a SOP solver inside to fracture the geometry dynamically. (picture 3) It works fine and the explosions are happening as planned. But since the geometry is concave, a convex collision shape is automatically created around it. (picture 5) And this causes the pieces created from explosions to be pushed outside instantaneously (picture 6). So I've searched for ways to handle concave geometry and this is what I found: Use the "concave" option in the "rbd packed object" node. It works! (picture 7). But it is excruciatingly slow, and this chess piece is part of a larger simulation with other chess pieces with similar issues. So in the end it would be difficult to work with everything being so slow. Decompose the base geometry into convex shapes. With the "convex decomposition" SOP for example. Since it produces several pieces, I can't display the result directly as the object is transparent (same issue as picture 2). And since I fracture the geometry dynamically I don't see how I could replace the simulated geo with some display geo in the end. Maybe I'm missing something here, but I don't know how to replace proxy geometry with display geometry when the proxy geometry is dynamically fractured. The "compound" option in the "rbd packed object" node The description of this option looks promising in the documentation, but it specifies that you need to use a node to generate some data, and that node is deprecated... It is replaced by another option called "Create Convex Hull Per Set Of Connected Primitives". But as far as I understand, your input geometry needs to be made of several "pieces" for this option to be useful. Is there anything I missed here? A method for generating collision shapes that doesn't involve breaking your geometry into several components?
  10. Hello, I've been working on an RBD simulation on an animated human object, but I'm having a problem blending between the animating geometry and the active simulation. Since it did not work in a SOP Solver, I tried using a Solver outside of the DOP in order to manually update the @deforming and @active attributes. However, that did not work either. I'm wondering if there was an issue in the way I was packing the geometry, or maybe in the way I was assigning the attributes. I would really appreciate your help. Thank you! rbd_sim_cleanup.zip
  11. Hello everyone, I'm trying to make a simulation based on the Applied Houdini chain tutorial. One problem I am facing right now is that the pieces that are brought into the simulation through a sopsolver freeze in mid-air. I have changed the sleeping time, but that doesn't work. There does seem to be velocity on the points. But they just freeze in mid-air. Anyone know a solution? BoxChain_RTJ4.hip
  12. Grouping DOP objects by Impact?

    Hi, First time posting here and relatively new to Houdini, so please forgive any poor use of terminology etc. Basically I want to group DOP objects, specifically RBD pieces, when they are impacted by another object. I want to do this so I can add gravity to each piece as they are impacted. When I look at the geometry spreadsheet I can see the Impacts data appear, but I don't know how to then group these objects by this. If it helps to visualize what I mean, I've made this puzzle globe made of 500+ pieces, and I'm throwing this ball at it to break it apart. I've got my sim working well enough, but currently gravity is not acting on any of the pieces, so when the ball hits, it's breaking the pieces apart but they are acting as if in zero gravity. So now I want to group this pieces as they become impacted either by the ball, or the pieces next to it, so hopefully by the ends all of the ball collapses. Thanks for any help, Alex
  13. Hello. I'm working on fluid sim which pushes RBD objects. RBD object's interaction(without Fluid) seems fine in Bullet and RBD solver, but when I came to make flipfluid to push RBD objects(not packed) forward, it seems not working. I tried days for fixing the problem, but I cannot find a solution for this... Am I missing something here? Here is the result movie and .hip file(H18.0) of my basic setup. Seasaw_RBD_x_FLIP_interaction.hip Seasaw_RBD_x_FLIP_interaction.mp4 Any helps, kindly suggestions are welcome! Cheers, koba
  14. Before elaborating, I am not a huge fan of the material fracture solution, which also gives similar issues. Apart from the node just taking 10 seconds to place. 10,605 children in 18.0 and >11,000 in 18.5. Also, the performance I was getting out of it was really not useable, so I'd always go back to looping over pieces and shattering (the usual) where I'd have control over the iterations and such. But maybe I'm just really too dumb to use the materialfracture correctly to get well tweaked results out of it, in a workable speed. So instead I've been trying to build a more lightweight solution to use which is a voronoi fracture which brickers the cutting geo and replaces the voronoi with a shatter. The issue is that the shatter apparently just gives bad output geometry when trying to fracture a second time, the geo is just completely broken. This is the base output which is marvellous. It almost stays interactive (0.1s / frame) while the materialfracture SOP would take around 10 seconds to calculate for a similar result. This is a preview of the cutting planes generated from the voronoi source points. When looping over the pieces from the first iteration, the outcome is always broken like following. I've tried quite some variations of loops, but apparently the first fracture just screws up the geometry. Any sort of cleaning/fusing would also give no better result. Is there any way the fix the boolean shatter itself? Or to get behind why it's outputting the fracture geo in the first place? The simple file with the asset included is attached. voronoifracture_plus_185_v01.hipnc Thanks in advance, Martin
  15. Hi there, I'm trying to learn vex, but I've run into a bit of trouble with the RBD solver. My goal is to apply forces to individual points on a model, and have the model respond appropriately. My first assumption is that I would use a bulletRBD solver to accomplish this, along with a POPForce node. However, this applies force to the center of mass of the object, which is fine, but I also want some rotational values as well. For instance, if I have a cube, and I apply force (0, 10, 0) to verts on the left side of the cube, and I apply the opposite force (0, -10, 0) to verts on the right side of the cube, I would like to see the cube spin. I know I can manually edit the @w attribute to add angular velocity, but do I have to calculate the angular velocity manually to make this work? Thanks for your help.
  16. 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
  17. Hello, I'm fairly new to Houdini, currently working on a RBD wood sim, happy with the current result. There's just one little piece that jiggers (geo overlap) and would love to only fix that specific piece so the rest is not affected. Thinking about 2 options but not sure how to do this: - Keep this piece attached to the bigger piece it originally was attached too. - Give this piece some extra velocity to create distance from the surface it's jiggering with. Thanks!
  18. Hello, I am following a tutorial on DOP Networks and Rigid bodies but when I apply a quickshade outside of the dop network and try to Import it as an RBD Object, it doesn't bring in the texture. I am not sure what is wrong? Can you please help? Please find attached the scene file. Thanks. TextureProblem.hipnc
  19. Animating/Keyframing RBD Constraints

    Hi all, I am currently learning the rbd bullet solver for class and playing with the settings more, I have broken up some geo with the rbd material fracture. I was wondering how I can animate the stiffness of constraints on rbd constraint node (or the rbd solver node) so that the geo starts to fall apart and then come back together as it doesn't seem to allow me to keyframe values. I also noticed there is a stiffness parameter in the rbd constraints node as well as the rbd solver. Is there much difference for these?
  20. FBX to Unreal

    I recently ran into a bunch of issues in getting fbx animation out of houdini and into unreal so I thought I'd share the process so that hopefully noone else needs to run into the same issues. Quick version: Use the ROP FBX Output in sops, don't bother with the labs RBD to FBX ROP Turn on "build heirarchy from path" on the FBX Output All intrinsic pivots should be zero
  21. RBD and its sleeping properties

    I set up a scene with crates that I want to get destroyed by a flip sim. figured out that I had to put a attribwrangle with i@bullet_sleeping = 1; so that RBD stays in place until the FLIP collides. The problem is now that with a little hit of flip to a group of crate the push activates all of them to break. I am a noob, but found that there is a threshold to control the amount of impact to activate the RBD. I just dont know which one of these it is and how to apply it to wrangler. bullet_angular_sleep_threshold bullet_ignore bullet_linear_sleep_threshold Documentation found here : https://www.sidefx.com/docs/houdini17.5/nodes/dop/rbdpackedobject.html Here is the original failed vid: https://www.dropbox.com/s/dl8ze5rv4vf6gse/Test.mp4?dl=0 Here is current failed test vid: https://www.dropbox.com/s/sa4sumxfqpqmdhq/Flud Test2.mp4?dl=0
  22. Color RBD Impact

    Hey, as a rbd user newby, I tried for 2 hours to get that, so if it can be usefull to someone Of course I guess it can be done in an easier and cleaner way, but anyway color_rbd_impact.hip
  23. Packed rbds and friction

    Hello everyone, I'm doing a simple packed RBD sim, and no matter how much I increase the fritcion parameters the objects never lose any velocity. Is this the expected behaviour? I've attached the .hip file. test.hip
  24. Houdini Senior FX TD, destruction!

    Hey Houdini community, Looking for a strong Houdini senior, remote work possible as long as you can somewhat align yourself with the PST timezone, we're located in Vancouver. If you identify yourself with the following characteristics, you may be a good fit for us: – destruction experience (vehicles, buildings, fire, smoke, complex RBD constraint setups) – works confidently & independently – can execute a VFX shot in his/her discipline from start to finish – pragmatic & quick problem solver – 5 or more years of professional experience in VFX – can work with rapid deadlines without overengineering setups Email with cover letter and reel please to: info@stormbornvfx.com We usually do high level hero shots, so that's something that absolutely has to be on your reel, otherwise we can't consider you. Have a look at what we've been doing recently: Cheers, Manu
  25. I'm having different results in my simulations using packed rbds connected only to a bullet solver vs when using a POP source to emit the rbd packed object into a popsolver/bulletsolver multisolver. The bulletsolver alone is giving me the expected results... I've seen some tutorials and tips by artists that recommend the multisolver approach, because it allows control of the RBD sim using pop forces and wrangles, and thats why I'm asking this. bullet_solver.mp4 rbd_multisolver.mp4