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Found 312 results

  1. Hey people, I heard this forum has a lot of really talented and technical oriented people who can help me out of my problem. At work I have to do some research and create a little scene where a car SLOWLY falls down a cliff. Imagine someone would push a car down a hill without a driver and it falls down to hell. So as a Houdini-Newbie I imported an OBJ of a car and declared it as an RBD-Object. My simple-geometry-plane is a static object. Through the gravity tag my car "rolls" down that hill and jumps over the cliff. But there is one problem. The center of mass should be more in the front of the car. Is there any easy way to move the CoM-point to the position where the engine sits? I tried different things like pushing the pivot aso. but nothing worked. It seems like Houdini tries to calculate the center of mass in the Object-Level with a bounding box and ignoring my custom moved pivot. Is there an easy way to define an exact point, where my center of mass is? Or is there any way to show it at least? My goal is, like you will see in the screenshot, that my car falls down a little bit faster in the front. Like it would behave in real world. Now it is pushing itself over the cliff until it gets over the center point of the OBJ. Thanks, Bastian
  2. Art Directed Wall Explosion

    Hey everyone, I'm trying to blow an object through a wall. I need a lot of control over the art direction. I have been doing my look dev in C4D where I can paint active vs passive objects. I can also have the active objects asleep until there is a collision detected. I have attached my working Houdini file. I haven't been able to figure out to paint active vs passive objects, so my workaround has been to alter the glue strength based on a color attribute that I created in the constraint network. This seems to work okay, but the wall get's knocked over when the collider goes through it. How can I pin this wall down to the ground? The tuts I've found all seem outdated for H16. Any help is most appreciated. Thanks! -Brian
  3. Art Directed Wall Explosion

    Hey everyone, I'm trying to blow an object through a wall. I need a lot of control over the art direction. I have been doing my look dev in C4D where I can paint active vs passive objects. I can also have the active objects asleep until there is a collision detected. I have attached my working Houdini file. I haven't been able to figure out to paint active vs passive objects, so my workaround has been to alter the glue strength based on a color attribute that I created in the constraint network. This seems to work okay, but the wall get's knocked over when the collider goes through it. How can I pin this wall down to the ground? The tuts I've found all seem outdated for H16. Any help is most appreciated. Thanks! -Brian WallExplo_Help.hiplc
  4. I have a load of RBD packed objects smashing on a Ground Plane, they're all intersecting by a consistent distance through the Ground Plane, the RBD packed objects are all convex hull rather than concave although changing between the two doesn't seem to make a difference. I've tried replacing the Ground Plane with a static box and trying different geo representations on it but that doesn't seem to work either. Any suggestions on how to fix this would be really appreciated! Thanks
  5. Hello OF, I have a small issue which I hope you can help with... I am creating attributes at SOP level to control the breaking of constraints in a SOP Solver in DOP's using the following VEX code in an attribute wrangle connected to 'relationship geometry' of the SOP solver. if (s@constraint_name == "pin_between"){ if ((f@torque>@break_torque||@angle>@break_angle||f@force>@break_force)){ s@constraint_name = "pin_broken"; i@breakframe = @Frame; } } My issue is that when I disable one of these attributes at the SOP level, the sop solver seems to interpret it at a value of 0, and the objects constraint will be completely removed on collision. Is there a better function to use than 'or' in this situation? An 'if else' seems more appropriate, but I am unsure of the syntax of that in this situation within VEX. Any help would be greatly appreciated. Many thanks in advance.
  6. I have two separate stacks of geo made using copySOP's, i am trying to get them to interact with each other. They do interact with each other but the constrains only effect one model, i can switch them in the merge but its only ever one that holds together, the other falls apart instantly no matter what the glue strength is. Ive put photos below and attached the scene file with the model that needs referencing in. New to Houdini so any help or advise would be greatly appreciated! Thanks PlateSimulationTest001.hipnc plate.obj
  7. I Have stacks of plates and bowls that i made with a copy node on one original model of each type of plate or bowl rather than importing each model multiple times. I want each object to be able to fall and smash independently which i am struggling to work out. When i make the stack a RBD Glued Object it either all moves and smashes the exact same way like they are being read as one whole piece rather than individual plates/bowls or they move individually but the glue errors saying "making objects from different solvers mutual affectors" so they cant smash. Sorry if this is a basic question i am new to Houdini, any help would be greatly appreciated!

    Hello! Do some of you sometimes use Fluid Force node? I want to have my fluid having influence on meshes, and I cannot manage to set the node properly. If you use another method for this, I would be happy to learn it. Thank you! leafNdrop.hip
  9. RBD not interacting!

    Hi guys, so I'm doing a scene where berries falling into a bowl but I use a sphere and a simple cup modeled to visualize then I realized when I use rbd object on the sphere and static object on the cup, the sphere doesn't drop into the cup but instead it drop just before the cup. I've been trying to figure out but I have no idea why it turns out like that. Any clue what happened? testyog.avi
  10. Hi guys, I'm started on a H16 sim where I have a cup of ice and fluid and another piece of ice that will dive in and float back up (animated). I've almost always dealt with larger water sims and don't have much Houdini experience with small scale sims I figured some people here have experience with such simulations and would like to ask if there are any best practices and tips here? I have some questions myself 1. How important is it to try to simulate and keep everything to scale for rbd and flip sims of this sort? I have found in my initial bullet tests that just trying to fill the glass with ice at scale tends to give me exploding rbd sims. In this case, I had the ice cubes and glass modeled in maya. When I brought it into Houdini I scaled it down by 100x to match the meter scale in Houdini. I tried adjusting the collision padding to stabilize the sim but to no avail. I had no issues when I worked at 100x scale. I'm curious if anyone else has experienced this? However, not working to scale meant that my flip sims feel larger in scale, like a swimming pool and not a cup. Increasing gravity 3x has helped the sim look more to scale. But that seems very arbitrary to me. I'm more inclined to work at a bigger scale as adjusting to smaller scales have given me all kinds of problems from unstable rbd sims to leaking water particles and decreasing water levels. 2. Is flip the the recommended approach for these fluid sims? I've seen sph being recommended. But honestly, I don't even know where the sph tools are 'hidden' these days in Houdini. And I know these days SideFX recommends flip for everything. 3. What is the best way to get some of the ice to interact with the water sim? Via density and flip solver feedback or the bouyancy force dop node? 4. Any tips on dealing with collisions and keeping things water tight in a thin lip glass that still needs water to splash out of the glass? When testing, I often found that it was very easy to leak fluid from the container even though my flip collision guide shows that there isn't any holes in glass collision. 5. Any tips in meshing the fluid with regards to lighting and rendering? I've seen it recommended that the water geometry be slightly larger then the glass. How are folks doing that with flip sims? I'll try posting an example file whenever I get to a good point. I really would like to benefit from the experience of folks who have done this sort of sim. Thanks in advance.
  11. 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
  12. Hi - so I have a particle system (from popnet old) of particles basically ramming into their nearest neighbor if their nearest neighbors nearest neighbor is them... and then I have one of the particles being deleted when they're about to collide. Now I want to do an RBD sim of spheres colliding with fractured spheres. So I separated the points into two groups, one for points that are acting as colliders which get spheres copied to them, and another group of points that exist for one frame (right before the collision) that get fractured spheres copied to them. I tried bringing these into a dopnet and making two RBD fractured objects... probably going wrong right about here.. The first RBD fractured object I set as my collider spheres and set it to 'Use Deforming Geometry' and the creation frame to $FSTART. When I watch it alone the animation seems to be working and the collision geo looks good. Then the other RBD fractured object I set to my fractured spheres and set the creation frame to $FF, when I watch this alone it seems to be working too. However when I merge them and plug them into a bullet solver everything goes crazy. I'm probably missing something simple, but I've been stuck for awhile now so figured I'd finally make my first post on here! The Hip file is attached, thanks in advance! particle_system_smash_test.hipnc
  13. RBS SIM

    Hi ,i use Houdini apprentice 15.5 for 3 months now and i have a problem with the RBD collision.In fact, i'm doing and exercice and the goal of the exercice is to have realistic mouvement when the tube push and object on the table. But the collision of the RBD Objects with the ground is not realistic. The thing is watch tutorials and i reproduce in an empty scene the tuto and it works fine with a simple object like a table and a cube, i mean when the cube is put onto the table the cube does not pass through the table. But in the scene you see bellow everything was working fine until I apply the glue node onto the bowl. After that the bowl the dinner plate and the waterglas pass through the table and it is the first issue i have.Secondly when the objects fall onto the ground the collision is not realistic.I need some one help to fix this problems.Thanks you
  14. Hi, I am trying to find a way to make custom shatter patterns with the make breakable button on the rigid body tool shelf. My scene has box - which is the default make breakable dynamic object. I would like to be able to custom shape the shattering in the same way as the object custom_shatter included in the hip file. Thanks! makebreakable_custom_v001.hip
  15. Chain RBD setup

    Hi again, I got a simple piece of geo here which I'm trieing to convert to an animation. I tried a wire sim with a wire capture, some constraints, a rbd collision method but This chain isn't willing to behave like a chain. More so if the chain is meant to follow an animated object while swi9nging around. Could anyone show me an example on how to make this thing work? Chain chain.bgeo
  16. Constraint RBD to animation

    Hey, how can I constraint an active RBD object to a static but animated one? For example I want that anchor to be constrained to that ring. A pin constraint just fixes it to a specific place. Tried wires but again this went crazy. So how can I get some realistic motion to his anchor? Also tried the oarent constraint which changes the constraint location from a static point in space to a goal object. Still no luck.
  17. Hey guys, working on a destruction shot which will involve a dragon thats being animated currently landing and somewhat destroying the building i have - Did tests with dropping spheres etc to get the constraints as i wished, then brought in a very rough 'previs' level peice of animation of the dragon i did - and as you will see from what i provide it doesnt collide correctly - i have tried increasing substeps - my collision volume matches my mesh almost perfectly, so really unsure what the issue maybe? Any help would be great (alembic and hip file below) and the youtube video link is to the latest flipbook i have showing the issue (please excuse my terrible dragon previs animation) Destruction_v2_t1.hip dragon_previs.abc
  18. Hi everyone, I made this setup to mix constraints between conetwist and glue, depending on angle value, i set the constraint_name in a sop solver plugged in the constraint network node, it works quite well but the resulting object is floating in the space... is anobody here can check my file and tell me what's going on!!!? apparently its not a subsanple or CFM, ERP issue ( i checked all this parameters and, nothing...) thx by advance, Best regards H TEST_PACKED_CONST_METAL_V002.hip
  19. Hi everyone! can't figure out why my cone twist constraint collpase at frame 2..., apparently this constraint dosen't care about restlength like other constraints... i tried all constraints, everything is just fine exept with this one, and cone-twist is exactly what i need.... I join a simple file based on a SideFX sample scene turned into what i need... thanks by advance Cheers! Twist-Const-Restlength.hip
  20. Hi, I am an experienced Software Engineer with a good eye for Visual Effects. I have over more than 10 years of experience in developing advanced software systems for simulation and animation companies. In addition, I've invested that last 5 years exploring and educating myself all about Visual Effects. Below is my demo reel. Please check https://www.linkedin.com/in/khaledabdelhay for more details on my technical/artistic skillset.
  21. Hi guys.I've been muckin' around in Houdini Indie 15.5 trying to get a very simple effect of pushing apart fractured geometry in all directions from the center (or any point of origin actually) and so far not very happy with the results.I've used the suggested “Magnet Force” method but to be honest this doesn't yield an acceptable result for a true bomb force effect. The various force nodes in Houdini seem to merely generate singular directional forces which is also not desired. I am aware of the method to set up a network of points or a point cloud of sorts that then all have a point force on them to drive dynamics however this is a convoluted and inefficient method at best.The desired result is very simple. If you are familiar with Maya which also uses Bullet dynamics, you may be familiar with the Volume Axis Force attribute which allows us to perform what I'm describing in one fell swoop. This is what I'd like to achieve in Houdini.Any insight into successfully achieving a true and accurate dynamic behavior of a bomb force would be greatly appreciated. Thank you kindly for your time and thoughts!
  22. I am trying to create a simple scene where balloons are tied together to an object using wires.(like in the movie “UP”).. Im having balloons as packed RBD object and the parent point(where balloons are tied) as a separate rbd object. and having wires also into the DOPnetwork as wire object.. Initially I dint simulate the wires but used the wire lines as a constriant network from SOP and made a spring constraint between balloons and parent using the wires as a constraint net, And It worked Perfectly. Now I am turning the wires into wire object and trying to constraint the top of the wire to the balloons and bottom to the parent object, I am having matching @anchor_ids on wires and balloons.. But It doesnt work properly. If someone can explain how to constraint wires with rbd , It will be very helpfull for me.. And if someone already have a scene file for related to this please share it , Thanks a lot in advance..
  23. Hi! I'm trying to replace some non packed pieces from a bgeo sequence to a hi-res version. I cannot simulate again so I need to find a workaround to "transform input geometry" in the dop import. I've tried the 'transform pieces' sop without success. Any suggestion? Thanks! transform_pieces.hip
  24. Hello, everyone A simple question, it's basically the title. By "increase" I mean increase by a lot. Everything the same, just turning on "Use deforming geometry" increases the sim from 60 frames in around 8 hours to 7 frames in the same time From what I could see it really takes a long time in the "creating collision mask" (or something of the sort) step. I have the VDB of the colliding object already cached in a SSD. So, is this normal? Also, a side-question, when you use a static object in DOPs, does it use the Bullet Solver or the RBD solver by default? I'm sure I saw this question here before, but unfortunately I can't find it
  25. Hi, I'm looking to create a paper cloth simulation for papers that twirl over the street blown by a slight wind. (like tumbleweed) I was thinking to simulate spheres with RBD and use these points to drive a cloth sim. But I can not get that interaction to work. The cloth object is not updating the position every frame. So I was thinking of using a constraint network. Has anybody got experience with this kind of simulation? Or other approaches I could use? Thanks!