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Found 82 results

  1. Hey all Could anyone point me in the direction to get a rigid body sim into UE4, I've got the Sim (it can be super simple) and I'd prefer FBX. Ideally I don't want deforming geo. The closest I've found is this workflow but it seems like the code isn't maintained. (This isn't mine) LINK https://vimeo.com/124874315 https://www.orbolt.com/asset/LaidlawFX::RBDFBXExport::1.0 I wanted to know if there's something I'm missing. Thanks once again in advance. Brian
  2. Is there a way to calculate the angular velocity from spinning points that only hold "N" "v" and "up", without using the trail SOP?
  3. Happy holidays everyone seen this question here before but tried all the suggestions with no results, I am manually deleting the constraints via attribute transfer. but some of the glue constrains reappear and stops some pieces mid-air. using packed primitives. am i missing an option somewhere? or did I miss a step?
  4. 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..
  5. I'm pretty new to Houdini and i've seen the "Active" attribute come up a few times in tutorials. I searched but couldn't nail down exactly why and where this comes from in Houdini. I get that it seems to pertain to DOPS and Glue constraints but I wasn't really clear on it all. I've seen people create it in sops and use it later in dops to activate things. My questions are: Is the "active" attribute a native attribute that nodes in DOPS looks for? Does it control all dynamics/force/glue or can you specify? Really any general info on it is appreciated! Thanks!
  6. This has been really getting on my nerves the past few days. I'm just messing around with particles and their attributes, connecting them to a Principal Shader for practice. I can get Emission to turn on(emitillum), I can control the intensity(emitint) but I cannot for some reason figure out how to control the Emission color. I know that Emission Color's parameters are: emitcolorr emitcolorb emitcolorb In my example I did a lowish-res flip sim and connected the velocity to Emission Intensity (@emitint = @v;) for example. However, When I colored my particles using a ramp and using the velocity channel, I figured I would try: @emitcolorr = @Cd.r ...and so on for Green and Blue. But, this did not work. I feel like I'm dancing around the answer but not able to find it after searching. I wonder if anyone else has run into this? Best, Stark!
  7. This has been really getting on my nerves the past few days. I'm just messing around with particles and their attributes, connecting them to a Principal Shader for practice. I can get Emission to turn on(emitillum), I can control the intensity(emitint) but I cannot for some reason figure out how to control the Emission color. I know that Emission Color's parameters are: emitcolorr emitcolorb emitcolorb In my example I did a lowish-res flip sim and connected the velocity to Emission Intensity (@emitint = @v;) for example. However, When I colored my particles using a ramp and using the velocity channel, I figured I would try: @emitcolorr = @Cd.r ...and so on for Green and Blue. But, this did not work. I feel like I'm dancing around the answer but not able to find it after searching. I wonder if anyone else has run into this? Best, Stark!
  8. Im stuck at this point in the particles debris. So my structure collapses to the ground with a typical rbd sim. But when i emit debris particles from them, my particles seems to stop falling after colliding in the top floor of the building and just stays there like a sleeping object. I am using vdb from polygons for my collision geometry which is the geo from the sims. Is there a way to tell the particles to not go still and fall along with the falling building. Thanks alot.
  9. Animal Logic's Matt Estela is our new GridMarkets Featured Houdini Artist! He manages to explain a complex and confusing topic such as DOPs in simple and efficient terms - check out his amazing tutorial here.
  10. I thought I was losing my mind when I first ran into this because I thought I was just having a brain fart. But, When using the "Voronoi Fracture Configure Object" I can't seem to only have particles emit from the newly created inner surfaces. I attached my scene file to this post. I know that if I do the fracturing (non-dynamic) in SOPs, I get the inside and outside group. I feel like this is something that is super obvious and I'm just not seeing it right in front of my face. Any help would be much appreciated! Thanks!
  11. This has been a very hard search to find an answer to. What I'm trying to do is add an initial spin/rotation to a DOP object. I attached a simple scene of a torus that has an initial upward velocity and then just falls to the ground due to gravity. Essentially, I'm trying to give it a "punch" that will cause it to spin - but not perpetually. A good example would be if you had an object that hit "glass." Although the sim would be physically correct, to add interest it would be nice to add a little spin force to the shards of glass on the initial impact. I can't for the life of me find a way to do this in DOPs. I'm sure I could be overlooking the most obvious parameter, but it's also Houdini and sometime the simplest task takes some finagling. Any help is appreciated! DOP_spin.hipnc
  12. Is there a way to freeze the transforms of a curl noise in a DOP popvop? I am running a point sim and my source emitter object is animated and rotated in world space. When the points emit, the curl noise added to the point position slides. I'm really not sure what to do in the popvop to freeze the curl noise. Ive tried using a popforce, however the curl noise does not seem to create the same shapes that the popvop does. Thanks in advance.
  13. I have a simple DOPs setup where I'm trying to understand the processing sequence.. While watching the Geometry Spreadsheet, I move 1 frame at a time: Frame 1: Field A is created (Field B visualization is also created) Frame 2: Field B is created (Using Gas Match from Field A, then a Field VOP creates volume data) Frame 3: Field B is now properly visualized. My question is, is there a way to get Field B's visualization as soon as it gets created (at frame 2)? Currently, visualization for Field B only activates on frame 3. houdini_solvers_study.zip
  14. Hey there, I am currently trying to simulate a (single) falling fir-branch like the ones you can see in this image: I would like to use a wire solver for that, but I am having a hard time to make the needles stick to the branch. How would you go about that? Desired setup: * branch as wire obejct (soft body behavior when colliding) * needles as wire object attached to the branch (soft body behaviour as well) * gravity in place, falling fir-branch, colliding with a ground plane. I tried the "Attach wires to surface" shelftool, but that attaches the selected wire points only to existing points on the branch-geo (which is low res, with just a few points). I would like the needles to be independent of the branch geo so that I can have a rather lowres branch geo (tube, less subdivs), and lots of needles. I would like to attach them like it is possible with folicles in maya, having them stick wherever they are on the surface, not having them stick to one of the input points on the fir branche geo. Using the point attribute "pintoanimation" or "gluetoanimation" also does not work. Doing so, the needles jitter around as soon as they are not in line with a points of the underlying branch geo. Do you guys know any solution for that? Thanks in advance for your time and help! Cheers, Philipp
  15. I started a thread a few weeks ago about using scattering and Voronoi points to create clusters from multiple objects. That thread is here: Clustering without fracturing? Luckily, that was solved after much confusion. However, now that I have that rendered with a few other stuff thrown in, I got curious about secondary fragmentation using those same clusters. The problem I'm running into is when I'm in DOPs and I add a voronoifractureconfigureobject. When there is collision's, there are no fracturing. But, If I un-cluster the bricks and constraints, the bricks will fracture as expected. I attached a photo and my file to the thread :D. Thanks! building_frag.hiplc
  16. Hey, I am trying to access/ passing data from different objects inside dops. Imagine obj0 has data called "impacts", which are a bunch of points and I like to pass this into obj1. Inside a gas particle to field wired to obj1 I like to access "impacts". I thought it would be as easy as putting down obj0/impacts into the particles parameter. But that did not work. The only way I found is copy/apply impacts to obj1 via fetch data dop, which I feel is a bit redundant. Any advice? Do I have the syntax wrong? Cheers Sebastian
  17. I am trying to figure out how to spawn new wire geometry within DOPs as it simulates. I create the full wire shape at sop level and I then I animate the deletion of its points backwards, from a couple of points to the full set. Of course just by importing this changing geometry, the wiresolver won't re-import it on on every frame. I looked into combining a SOP solver and tried various approaches, but none worked so far. Deleting points in the sop solver didn't work. Then I tried deleting the primitive, adding or even copy (to aquire all the wire attributes) one point at a time and connecting them all with a new line primitive. But that didn't work either. Any ideas? thank you
  18. I may be missing something in the voronoi fracturing SOP, but I can't figure out a way to create clustering without causing fracturing on the geo. For instance. A standard brick will or just group of geo that clusters into groups using the scattering method so I could make the cluster groups bigger or smaller. I feel like I'm overlooking something so obvious, or maybe I have to create proxy geo that is clustered and test if the brick particles are inside of it to group them? Ah, now I've just confused myself. I hope a few of you have run into this problem and have some incite. Thank you :D!
  19. I'm setting up a system to source into a smoke sim directly from particles, without having to add a "geometry" data field to the root of the dop object. It works great when everything is manually set up, I can create a reference to the "geometry" field which is nested under the microsolver. As an example, plugging in a SOP Geometry dop into a gasParticleToField dop, the "geometry" dop field is created as subdata of the gasParticleToField microsolver. So the path to the geometry field is: /obj/GEO/DOPNET:obj0/Solver/gasparticletofield/Geometry As opposed to attaching a SOP Geometry to the dop object itself, which creates the Geometry field at the object root: /obj/GEO/DOPNET:obj0/Geometry As I said, it's easy enough to manually copy and paste "Solver/gasparticletofield/Geometry" into the gasParticleToField dop, but I want to make this a tool, so I need a procedural way to reference the path to the dop data. I've tried most of the local variables available, but none of them seem to give me that functionality. Essentially, I'm looking for something that will return the path to the dop field when called from a dop node. Example: when called from the gasparticletofield node, it would return "/obj/GEO/DOPNET:obj0/Solver/gasparticletofield/" or ":obj0/Solver/gasparticletofield/" or "Solver/gasparticletofield/". Basically, what happens when you drag a dop field to the textport. Anyone have any advice for relative references for dop fields?
  20. Hey guys, I have two quick questions. I'm trying to learn how to make constraint networks by hand. I've noticed that for some reason, when I define the strength of my constraint in sops using a wrangle sop, I only need relatively low values. However, if I delete strength attribute from my wrangle sop and control the strength in dops using the 'Glue Constraint Relationship" dop, the values needed to achieve the same effect suddenly become massive. For example, when I define the strength in sops, I only need a value of 10 to get the effect I want. However, controlling the strength in dops (no strength attribute defined in sops) require a strength of 100,000 to achieve the same outcome. I'm wondering why there is this massive difference between sops and dops. Also, say I wanted to add a second fracture object to the sim (unique the first one), with a constraint network of its own, whats the best way to go about bringing the second constraint network. From my understanding, adding a new object is as simple as adding a second RBD Packed Object dop, merging that with the original, and plugging the merge into the rbd solver. But with constraints it seems I would need a new constraint network dop and a new glue constraint relationship dop for every set of constraints. I'm just wondering if there a way to do it all through one constraint network dop and use multiple glue constraint relationship dops, similar to plugging multiple RBD objects into one RBD solver. constraints.hipnc
  21. &I66i5iy I ran into this problem where I am exporting multiple pieces of geo from 3ds Max. What's really odd is I could have them act the same as internal Houdini geometry. In my case I have bricks. However, in DOPs, when I go to so fracturing with the Voronoi Fracture Configure Object - all of the bricks just collide without fracturing. If I replace the bricks with anything native to Houdini it fractures as expected. Is there any reason why this is happening? As an FYI - when I imported the geo from Max I had to scale down the scene from 1 to .2. So I don't know if this might be throwing off the mass/density. I would upload the scene but I can't because it's a production shot. I will work on making a proxy scene to upload today if it helps. Thanks!
  22. Hello! I'd like to share with you an interview with two FX artists from Naughty Dog who worked on Uncharted 4: A Thief's End. In it, Neilan Naicker and Ray Popka talk about using Houdini for doing destruction, rigid body fracturing, ingame dynamic rivers/flowmap generation and spawning thousands of running chickens! See full interview here: http://www.sidefx.com/stories/fx-adventures-in-uncharted-4-a-thiefs-end/
  23. Hi all, Am trying to tweak a scene file that was passed to me from here (apologies, I don't know/can't find original poster, so can't credit). It's a wire sim where points are activated based on their Y position - And I'm trying to tweak it to be based on color. I've worked a nice way to animate my colour across the points in a way I like, but my question is: How do i get my point color attrib to update per frame in the dopnet? And how do i associate it to the gluetoanimation value? Been really trying to get this going today, but to no avail... Any help or tips gratefully received! activate_sim_based_on_color.hip
  24. This roadblock stemmed from this thread that was started here. I thought, wow, this is awesome, you can do so much - such as fracturing. However, when I tried to just do a very quick "let's see if this works" setup in my DOP network by adding a Voronoi Fracture node; it ignored it. <~This was using a Packed Rigid Body Object (I've attached my scene file without the voronoi node). However, when I switched the Packed Rigid Body out with a Standard Rigid Body object, it fractured. I've been trying different methods to the best of my new abilities to get this to fracture, but I can't find an answer or figure it out. I took Matt Estela's setup from his site posting here and tore it down to it's barest of bones. In short, I'm trying to get the spheres to fracture on impact using the packed rigid bodies that are emitted from the POP Source. Blah, this forum is the best. Thanks for any help you can give. fracture_test.hipnc
  25. I'm trying to figure out a way to take 2 objects in a merge and then randomly output 1 or the other to a CopySop. Simply, I have the copy connected to particles and I just want the shapes to randomly go to a random particle. Right now(for obvious reasons) it's just taking the 2 merged objects and assigning both of them to each point. I attached my file and left a blue sticky under the green nodes where the issue is taking place. I do have questions regarding this problem. - I know I can merge multiple objects and then in the DOP node that has those particles, just use packed geometry to achieve this. - Is it even possibly to do what I'm trying to acheive in the way I'm trying to in my example file? - Which method is best? - if one is better than the other? Many thanks in advance! I'm always unsure if I'm being super confusing, so I apologize if I am. dop_crack_part.hipnc