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Justin K

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Everything posted by Justin K

  1. Anybody have any experience working between the two packages? Currently the goal is to build the clothing design in Marvelous Designer-- on models rigged and animated in Houdini. As far as the plan, it would seem there are to basic approaches-- 1) send the animation into mixamo from houdini then do the cloth and simulation as one take, problem is this would mean any interactivity between the cloth and other simulations in houdini (rain, solid objects) would be limited. 2) OR T-pose the character -- send the character to mixamo for the cloth design and then back into Houdini for the actual cloth sim and everything else. Any thoughts or opinions on this? Pretty early in the process- but just looking for some suggestions and ideas--and potentially warnings about headaches lol. Thanks in advance!
  2. Marvelous Designer to Houdini

    as for this approach-- one concern I have is the time alloted to have the sim 'calm down'---if i was to do the cloth in marvelous designer on just a tposed character and then send it to houdini for an additional sim arent you encountering this settling twice? and would this potentially cause issues? Just curious ?
  3. Marvelous Designer to Houdini

    thanks for the tips both of you--- the tpose thing was something I actually had in mind to begin with--getting the clarification that that is the way to go is appreciated.
  4. For anyone's edification! Here is the correct way to set this up–thanks sidefx support! FLUID_CLOTH_TEST_v004_SIDEFX_SUPPORT.hiplc
  5. Hello!--im trying to get a piece of cloth to interact with a fluid sim. I think I am supposed to use the fluidforce dop for this. Im using the examples in help as reference. The examples however are only for wire set ups not cloth--though they say for cloth as well. When I try and use the setups (with the needed tweaks for cloth) there is no real interactivity. If I reorder them and put the cloth first the fluid recognizes the cloth as a collision object, but doesnt affect it. The other way around I get nothing. As far as I can tell from the wire setups, the fluid needs to be sourced first anyway. Im trying some alternative approaches with sop solvers and not--but the results are pretty awful lol. Any suggestions? Thanks! FLUID_CLOTH_TEST_v004.hiplc
  6. Hey all, Pretty serious question from me here. Ive been trying to work on a scene including cloth over the last two weeks, and have come to the conclusion that the cloth solver does not play with other solvers. It does not support mutual affecting relationships as far as I can tell, unless the second object is another cloth object–which kind of defeats the purpose in certain situations. Am I correct about this? Basically I want to hit a piece of cloth with a bunch of RBD objects (very small ones), and send convincing cloth like currents through the surface (not sine wave based like it would be with the ripple solver). The objects have to respond to the cloth though, and bounce or split off the cloth. Im Basically simulating the effect of hail or large rain drops interacting with the cloth. I have tried two main approaches. 1) static objects based off of particles sims. I got some help off of the forums to trick the static object into seeing the same number of prims each frame so it didnt error out (http://www.toadstorm.com/blog/?p=307) thanks tanto!, but overall, this solution fails because the static objects dont interact with the cloth mutually, the static objects just pass right through and so the cloth literally snaps back into place after the object passes through. After this didnt work I understood that I needed a mutually affecting object relationship here. So I turned to RBD objects. Got some more help on this so I could still emit from particles first hand (https://lesterbanks.com/2016/08/easily-turn-houdini-particles-to-bullet-rigid-bodies/ [lesterbanks.com] ). However, the cloth simply will not interact with the bullet objects. I read somewhere to use the RBD solver instead and bypass the packed objects aspect, but when I did this, even with collision type set to volume, the pieces just fell through the cloth. I saw an old post this where it was asked why the cloth solver didnt play with the others, but that was in Houdini 14. Has this not changed, or am I missing something? If anyone can shed some light on this issue id appreciate it! Today Im switching to the bullet solver using grains (seems to be what all the cool kids are doing anyway – this is my main resource https://vimeo.com/219204848). Im just at a point now where Id like some clarification on this. The down side to going the grain method is I have less control over the cloth object behavior –johnny farmfield mentioned casually that it works great as a replacement for cloth, provided your working with silk like cloth. Thatbeing said, I will be getting a serious speed boost which will be helpful. Overall Im just looking for some clarification on this (Im more than happy to be proved completely wrong here . Thanks in advance! Ive attached a scene file if that would be of any use. CLOTH_&_RAIN_UPL (1).hiplc
  7. Hey all, Im having some issues with object interaction. Im trying to get some spheres emitted from a particle sim to interact with cloth as either a static or rbd object (see pic). As a ntoe I posted this already in the wrong thread by mistake . I have encountered problems with both methods. The static object approach errors out because the geometry is changing on a per frame basis- each frame has a changing number of spheres. Because the particle sim was run over the frame range, the number of primitives copied to the pts is changing each frame--this causes the static object to error out (see pic) On the flip side the RBD object technique doesnt work-- because I cant import animating geometry at all (or perhaps I just dont know how--there seems to be some stuff on the sidefx thread-- but im not sure it applies here? https://www.sidefx.com/forum/topic/30392/ ). Overall Im getting the impression that animation on packed objects is intended to happen within the solver itself, not beforehand.? The very last thing I cam across was this---this setup allows you to emit rbd objects per frame from another pop setup-- https://www.sidefx.com/forum/topic/34178/ but if the particles are animating the rbd object will duplicate each incoming object per frame. see pic. Any suggestions for how to accomodate this? I would like to keep the rain sim separate from the cloth work if possible, but cant find a workaround for the above issue. As far as due diligence I have looked at alternative stuff on the grain solver side (Johnny farmfield stuff) and have tried working with active and deforming attributes to get a solution, but no luck. Ive simplified the scene and kept only the basic stuff. And also added the latest scene file I came across Thanks in advance for any help! RBD_from_particles.hiplc FROM_HELP.hipnc
  8. As a note Im watching the particles masters class from houdini 13 to see if I can get any tips and info--the last 15 minutes seem like they might have what im looking for
  9. Hey all, Im having some issues with object interaction. Im trying to get some spheres emitted from a particle sim to interact with cloth as either a static or rbd object (see pic). I have encountered problems with both methods. The static object approach errors out because the geometry is changing on a per frame basis- each frame has a changing number of spheres. Because the particle sim was run over the frame range, the number of primitives copied to the pts is changing each frame--this causes the static object to error out (see pic) On the flip side the RBD object technique doesnt work-- because I cant import animating geometry at all (or perhaps I just dont know how--there seems to be some stuff on the sidefx thread-- but im not sure it applies here? https://www.sidefx.com/forum/topic/30392/ ). Overall Im getting the impression that animation on backed objects is intended to happen within the solver itself, not beforehand. Any suggestions for how to accomodate this? I would like to keep the rain sim separate from the cloth work if possible, but cant find a workaround for the above issue. As far as due diligence I have looked at alternative stuff on the grain solver side (Johnny farmfield stuff) and have tried working with active and deforming attributes to get a solution, but no luck. Ive simplified the scene and kept only the basic stuff. Thanks in advance for any help RBD_from_particles.hiplc
  10. Hair Shader Tips

    Hello all, Doing some experimentation with the hair shader. Just curious as to what the general reviews of it are when it comes to getting hyper realistic results? I have been playing around with the hair and fur system on the technical end and love it. The thing is I am struggling on the shader end. Im not that experienced with shading to be honest, and at the moment I am paintstakingly experimenting with parameters and lighting in hopes of getting something that works. Dont mind the experimentation but I stumbled across this And became a bit curious. I know it is two years old, but is there something fundamental in the default houdini shading model that leaves things to be desired when it comes to hair? The arnold shader when I used it in maya seemed to get me realistic results fairly quickly-- https://support.solidangle.com/display/A5AFMUG/Standard+Hair but I want to use Houdinis fur system, and would prefer to use mantra to arnold if I can. Id like to point out that the masterclasses put out by SideFX have been extremely helpful for learning the tool itself. Thanks in advance for any help or suggestions! If youd like a temporary file Ill be happy to provide one--but im just working on spheres and grids at the moment, and trying to match hair to a couple references I found.
  11. Skin Shader Bug ?

    Hey all, This is the result the skin shader is giving me out of the box? Something seems off with this-- it is happening on both windows and mac machines with different video cards. Are there issues with the skin shader or am I just noobing out here lol? Ive attached an IPR window and then a final result. The skin shader is applied to the ground plane-- not the hair strands. Thanks!
  12. Thanks Adrian-- implementing and working with it now.
  13. Hey all, posted this a bit ago but I am updating the post with a lot more context. I am trying to find a way to render volumetrics in houdini. More specifcially, I have a night scene, with street lights. Because it will be raining there will be volumetric influences on the light sources. I want the light sources to be cut with god ray like light patterns, or at the very least have convincing fog throughout the scene. I am struggling to achieve this affect with mantra. The first two images are what I am using as reference. The first is the scene I am trying to emulate in 3d --complete with a rain sim and an umbrella rig (ya the same one from a previous post ---all help was apprecaited) (source: https://angelganev.deviantart.com/art/City-Nights-III-Day-82-700866138 ) pic 1 The second is an inspiring render I cam across with very well designed volumetrics in the sky--and convincing wet maps on the ground level (source: https://www.behance.net/gallery/35226551/52Hz ) pic 2 The focus now is on the volumetrics. I have now attached the master scene file with the assets included as a zip in hopes of getting some detailed help--its a pretty simple file. Now, Ive been trying to use this as a reference https://www.sidefx.com/tutorials/god-rays-light-beams-through-volumes-updated-20170508/ but am struggling with the implementation. Something in materials seems to have changed in houdini 16 (or I am more likely just missing something). Overall, the suggested technique seems to be to simply apply a volumetric shader to a bounding object and use that to apply volumetrics to the scene. This approach seems to work as intended but only if the camera is not within the bounding volume which in this case defeats the purpose. See pics 3 and 4--one pic shows the volumetric box from an external view-- and shows its affect on the light sources--the second is inside the volume, where nothing seems to be happening--even if I try to trick it an dreverse the normals the result is just wrong. Is there a way to do this on the shader level? I know I can use an isooffset and build volumetrics on the object level, but when I was working with isooffsets my render times were ridiculous. I dont want to have a scene with crushingly long renders if I don't have to. It was pointed out that if you keep your volumetric sample 'cranking' on the material rather than scene level your results will be much faster--hence the reason Id like to implement the shader level approach if possible. Again, any help would be appreciated, Thank you! Painting_JK_01.zip
  14. Joey struggles here.. Is it supposed to be located here?
  15. thanks adrianr-- I am currently using 16.0--16.5 is not working on MAC OS for me :(--at home I have 16.5 but not at work.
  16. Hey all, Doing some lighting testing here. I have some light instances within a fog volume (just a fog volume object with a generic fog shader). I would like to be able to mask out everything BUT the lights from the volume at this point (working on emulating street lights--not very far yet lol). I have heard people mention categories being used in similar situations, but I have never really used categories, so any suggested alternatives or a breakdown of a category set up for this situation would be helpful. As a side note at some point Id like to have a fog volume that is a bit more aesthetically pleasing than this, but the two approaches (besides the quick and dirty current one) I have used so far are fairly slow. The first is using a bounding box wrapping the entire scene, then an isooffset, and finally some volume vopping to get some cloudlike whispy variation and density in the air, but the render is really slow). Another alternative, bounding box with a volume shader was slow as well, but perhaps I am looking at setting up the volume itself incorrectly as well? Still, at the moment, figuring out how to do light masking on instances is a larger problem. Thanks in advance! I've attached a file lighting_v02_upl.hipnc
  17. Hello, Getting really frustrated trying to implement a seemingly simple concept. Im trying to build a simplified umbrella rig. There are only three parts- stem-- stretcher- rib- and - tube-- see picks. In my attached file, on a sop level, I cant find a mathematical way to keep "the stretcher" line objects to stay the same length, and have the anchor point on the tube move up and down the tube as the umbrella opens and closes. (in the pics Ive attached you can see the issue). Originally I thought that I could tie the perimeter attribute of the line to the carve position on object--basically retaining the perimeter --but I couldn't devise an expression relationship that works. I actually went and tried to do this on an object level using rigging tools and got even more frustrated- moreso because Ive never used the rigging tools in Houdini----. Bit frustrated here-- this seems like it really should be trivial. If anybody has a way to do this on a sop level Id appreciate the insight. And if anyone could show me an example of how to get it to work with a simple IK rig you'd be my hero. Thanks all. umbrella_rig.hipnc
  18. Thanks Noobini, Implementing your workflow now. I did a bit of a break down of the math that you did for my own sake--felt like it wouldnt hurt to put it here for anyone else. EDIT: opposite side is not the distance between pt3 and the origin, it is simply pt3s x value--its distance in the x axis only
  19. Hey All, What is the most straightforward way to bend a line (object 1) towards a point (object 2) animating in space. Id like to do this on a point level if possible. I already have a rudimentary setup-but it is not working perfectly. Currently I am using a bend sop, and then simply specifiying the Goal direction as the second object. Fur such a rudimentary approach it works rather well. The problem is it is not 100% accurate. The last point in the line does not always point directly at the point in space. Im getting the sense that if I really want the object to bend towards the point perfectly, I might need to use some matrix rotations on a point level (using a for loop) --but that is beyond my skill at this point. Any suggestions? Thanks! Ive attached a file bend_follow_line_upl.hipnc
  20. Bend Line Towards Point (Update)

    Made some progress Did some quick wrangling, trig, and a bit of matrix math. Repurposed some code from a post that I found a while ago. Many thanks f1480187! Still working out some kinks- bend line_upl.hipnc
  21. Hello all, I am sending some geometry pieces back to the origin to do some manipulation. Im using a for loop, and within the loop Ive at least managed to move each piece back to the center. The issue is rotation. I want the objects existing normals "N" to be flush with the x axis while working, and the objects 'up' vector to be flush with Y axis {0,1,0}. I know I can use the arccos(dot(up, up2) function to get the angle I need, (and have done so), my issue is I cant figure out how to rotate the pieces accordingly. So basically--object incorrectly rotated at center-- its existing Normals should face towards +x {1,0,0}, and its "up" vector should face towards {0,1,0}. After work is done, Id like to be able to send the piece back to where it came from, but am a bit stuck. Thanks for the help!!! rotation_reset_at_origin.hipnc
  22. Thanks Tomas!-- a much more straightforward method than I was conjuring up. Solved!
  23. Hey, So I have made some progress. I found way to orient the object the way I desired within the loop for work purposes. Working on the setup for transferring the rotations back when the time comes now. now. Let me know if you have any suggestions all! rotation_update_01.hipnc
  24. EDIT: I figured out a way to do this: I you generate the group prior to the loop the iterations will merge with each pass .
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