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Justin K

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About Justin K

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    Justin K
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  1. 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 ?
  2. 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.
  3. 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!
  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. 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
  8. 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
  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. 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!
  11. 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.
  12. Thanks Adrian-- implementing and working with it now.
  13. Joey struggles here.. Is it supposed to be located here?
  14. 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.
  15. 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
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