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Everything posted by Pancho

  1. IK solver mayhem

    Hi, I try to bend my head around the kinefx ik solvers. I'd be glad if the "ik chains" would solve more than a regular leg or arm, since I have more than just an elbow joint. But it doesn't. So there's either the "solveik" in the rig vop left and the "fbik". Unfortunately the solveik doesn't seem to respect my initial transforms and comes up with something which looks like a curve solver, but a twist vector is present in the solver. While the fbik seemed to be promising in the beginning, it easily ends up totally garbled. Initial joint transforms don't seem to matter for the solve and the perfectly aligned joints move into totally wired positions. Twist vector is missing. Bit unpleasant situation. Put the three possibilities into the attached file. Is there anybody who found an solution for this problem? How can I tweak the "solveik" that it respects the neutral joint positions/rotations and/or is there a way to have an up vector for "fbik"? A multiple joint chain should be so difficult to solve in 2022. At least not in Houdini... Cheers Tom ik samples.hiplc
  2. IK solver mayhem

    The only difference I can achieve in the solve is to change the rest angles mode. No rest angle = Screws instantly up into the bridge/curve like shape. The other two don't seem to make a difference. : (
  3. IK solver mayhem

    Thanks so much for your scene file. Indeed in your example it works. In mine it did not, until I rotated my chain to be aligned with the z-axis. Then it worked too. Not sure how to solve this. Probably related to the root or local transforms?
  4. IK solver mayhem

    I wanbt to add that I'm constantly getting python viewer state event callback errors as soon as I touch a kinefx node. Let's say in 50% of my interactions. I click them away ("ignore future errors"), but they keep on coming back. Not sure how to deal with that and if is part of the problem.
  5. IK solver mayhem

    I'll immediately update and see if it makes a difference. I'm on 19.0.498 here. Didn't think about it to be a possible bug. Actually it's annoying that they didn't make the sop solver fit for the task to solve multiple joints. Will look at your file asap. Thank you very much so far!
  6. Which constraints for wood RBD?

    What kind of constraints should be used for wood fracturing RBDs? I tried Soft constraints so far to achieve some kind of bend behaviour during impact and use a SOP solver in DOPs to remove constraints above a force, torque or angle threshold. Is this the way to go? Or is it possible to mix softbody behaviour with the RBD one? E.g. a branch should bend before breaking. I currently "achieve" this look with a highly fractured RBD and soft constraints, but on the surface you would be able to see that it's actually breaking and the bend is achieved by rotating/moving pieces individually. BTW, did vellum change the RBD workflow for fractured stuff so far? Cheers Tom
  7. Write a python script to collect all the parms of the selected nodes you like to display. Display the formated parameters in the console and copy them into the font node. p.label() is the name you want to display, p.name() the name of the parameter which you need to connect to the node path, like "/obj/geo/" + "xrows".
  8. I checked the docs, but unfortunately couldn't find anything yet. I wonder how to constrain grains together to achieve some mud/soil like behaviour (clumping) with vellum. Vellum creates the GEO and CON output, so how do I create the constraints? I managed to create attractionweight and -stiffness attributes on the grain particles (before GEO output) in order to come up with different behaviour, but these aren't enough to produce proper clumps. Cheers Tom P.S.: If I transform (move) the GEO output, do I also need to move to CON output?
  9. Open world roads

    Hi there, trying to bend my head around this for a few days now. Since I'm creating my terrain and roads (using pathfinding and manual approaches) in Houdini, I wonder how to create/import these roads inside UE4. I've seen a lot the videos on road creation inside UE4 using splines. The basic seems to be to pathinstance and pathdeform small chunks of road. Very memory friendly. But in all cases the splines were created inside UE4. With an open world which might change during the developments every day, this seems to be a very destructive workflow. Since I already created my road inside of Houdini (as a nurbs curve, primitive curve or as geometry), what do I do with it to finally create it inside of UE4? Importing the geo seems like a no go, since in an open world this mesh might be really heavy, although it would be easy to create the geo inside Houdini giving me full control over most parameters. Would UE4 slice this mesh in a memory friendly way, so that it can handle it? I couldn't find anything yet on importing spline components via an assett, to create the streets with a blueprint. I imaginge since UE4 uses instances for these roads which are bend along the spline, that this might be a good approach, but how would it work practically? Most of the videos covering this subject show the creation of a small racetracks or something similar. A no brainer in terms of performance, since the geo can be easily imported. But in an openworld with 20km of road this seems to be not the right option, or? If you have any experience on this subject, I'd be glad if you could share it. Cheers Tom
  10. Mplay and python

    I can't find anything in the docs nor the web. I'm so sick of entering manually details into the save dialogs in the mplay window. I actually want to script a shelf button which puts in a filename related to my scene and take, chooses the format, adds a comment and probably some other settings and presses the "save" button in one go. Unfortunately there is no obvious documentation popping in my eye. Can it be done? Or what would be the alternative? In a production is feels so clumsy to enter these parameters over and over again. Cheers Tom
  11. Open world roads

    Sounds like a good project for getting into lidar hardware. For this purpose a rotating one might be nice, but one which could be carried around is probably even better.
  12. Open world roads

    Ah, don'T build one. THe ones I've seen are more a gadget, than a lidar scanner. The two from DIJ are between 800-1500€ I think. ONe seems to be a single scanner, the other a triple one. Both are not rotating, but scanning in one direction. Wonder whether the speed of a car at 30-50km/h would still deliver nice results. Scanning distance is something like 40m max as far as I can remember.
  13. Open world roads

    Wow! I'll check the wip! Did you capture the lidar yourself? Need to capture something like a long road. Thought to mount a lidar like the one from DIJ on a bike, but not sure whether this will work. Tried photogrammetry. While Nuke is able to retrieve a pass the point clouds are a mistery. Agisoft on the other hand comes up with great points clouds, but looses the spatial sequence, so instead of one long passage, you get a wired mix of small chunks. Still looking for a solution. Something which works as Nuke could/should work.
  14. Open world roads

    I just used UE4 as a render engine for some animations. All this VAT to export animations is a pain. Houdini engine should take care of this. The videos about the LABS tool pretend that it is simple, but it's like "Pitfall", the C64 game. I guess I don't need to get into details. The nurse was pretty busy whiping away the foam from my mouth for hours, days, weeks? : ) The pain with every new package is not doing some stuff, but to get the philosophy of how things are done. In H I don't care about a few 1.000k, but in Unreal? So just the get info whether it's bessed to export spline, geo or whatever is difficult to get. That's almost as terrible as converting a receiving high res DEM models! : ) Cheers!
  15. Open world roads

    Thanks for the reply. Funnily I just started to look at culling after it was menitonend in the "From ant to space" (or something) video from Unreal. THe guy presented it in combination with world space displacement for flowers. The further away from the camera, the lower the instances would be placed. If they are beneath ground some form of culling lets them disappear. I guess cutting the street into pieces would be the way to go. Probably the heightfield could still carry the color information of the street even if the geo isn't there anymore. In combination with LODs this could work nicely. Will give it a try asap! Are you familiar with UE4?
  16. Open world roads

    Ha,ha! THanks for the tip!!! : ) Watched it already. But I was a bit disappointed when he just instanced the rails tracks with visible gaps. : / Hoped that I would find the secret in this video. Unfortunately I can't find anything on the web so far covering this topic in regards to what splits my brain. I just can't tell which way I should bring in the geo so that it suits the needs of a game engine. Probably I could just generate the road mesh in Houdini which would be a no brainer. But since the street is long, how would I prepare the geo in order to just load parts visible to the camera or reduce it's LOD in the distance or do something else to it that it is UE4 "safe"? Bringing in a heightfield is one thing, bringing in the instances another, but the roads... ???
  17. Flip fluid "noise"

    Hi there, I just wonder where these lines/ripples come from. They look ugly and not realistic. My velocity volume is about 200 voxels in width and covers the flip sim pretty close. So I guess that's not the problem. Has it got to do with substeps or the grid size? The sim runs very slowly so changing settings and get "instant" feedback is a "small" problem.... : ) Roughly 36m particles and 6m per frame. Cheers Tom
  18. Digital Assets and the Tab menu

    Interactive -> Shelf Tools
  19. Digital Assets and the Tab menu

    In H18 there's no Tab called tools anymore. What has changed and how do I accomplish it now?
  20. Instance rotations in asset

    That would indeed be a game changer. So far I thought it's not used in this way, but rather for deforming geo, like a flag in the wind for example. Will need to look into this option closer. Thanks!!
  21. Starting to get a depression. What seemed to be the most simple task turns into a headache. I instanced cogwheels in my asset which turn nicely. Different sizes, different rpms depending on their teeth/diameter. Animates brilliantly in Houdini. Since the cogwheels are instances I thought they would turn nicely in UE4, too. NOPE. I guess it's about that the asset just cooks once and then is "stached" by UE4. No more "Hey, do you have updates concerning the rotation of your cogwheels? I'd like to spin them. If you want to." questions between the engine and unreal. It's 2020 and turning objects inside a 3d app isn't anymore state of the art, but I guess unreal makes an exception. How can I spin a lot of cogwheels in UE4? Just by setting an individually angle on each instance. No collisions or so required. Everything gets calculated by time and diameter. That's all. If a blueprint is the only way to go, how then do I access the instances in my asset and update their rotations or even positions? Technically? Is there something like "get all instances by name" function which creates an array I could loop over and update values? Looked up the web for half a day without success. If you have an idea how to do that, I'd be really happy to hear about it. Cheers Tom
  22. Instance rotations in asset

    Thanks for sharing this idea. Came across this method, too. I just hope that there's a way to just rotate the instances. Otherwise I would need to convert all instances to geo which creates a lot of vertices. Managed to create a blueprint which turns my asset. Quite easy. What's missing now is to get to the instance geo and do this per cogwheel. If this is possible, than I would at least find a way to come up with several solutions for my work.
  23. (novice) $JOB vs $HIP

    But that assumes that it's just in the first subfolder of "scenes". In larger projects there might be several subfolders and the way of dealing with it by going up one level won't lead to the correct directory. I haven't fully understand how to set up the $JOB variable yet. People seem to set it up in their houdini.env file, which doesn't make any sense to me since this is global, right? I switch projects many times a day, so this needs to be setup somewhere in the scene itself. So, how and where is it done? Cheers Tom