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tagosaku

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Everything posted by tagosaku

  1. Hi, The picture shows an object , create > test geo > add velocity > vdbFromPolygon with vel field > visualize velocity. I wonder how to split velocity to tangent velocity and normal velocity. I guess we don't have a node to do it by one click, and need to work on volume vop/wrangle. If anyone knows how to do it, I will appreciate it, thanks!
  2. Hi, I have general questions about FLIP. For instance, there are splashes like an attached picture. If I want to change velocity or delete splash/spray, I think there are 3ways. The FLIP concept could make it tricky because FLIP contains particle and volume fields together. Thus, questions are: 1 - in general, if I want to change velocity or delete splash, do I need to modify the both of particles and field together? Or just modify one of them? 2 - It's kind of similar question as #1, but, when we use sinkFLIP and pump and sourceFLIP; 2a - pump seems to add velocity, but it's strange why source volume sets copy, and velocity sets normalized?? It should set source Volume none, and set velocity normalize OFF. Also, why don't we use pop node to change particle velocity directly?? 2b - sink seems to just kill particle, but why sourceVolume is maximum? It should be subtract although it's not exist.. And there is still surface volume exists after deleting particle... Can't we use just pop kill to remove waterVolume/splash? 3c - sourceFLIP looks just adding particle. I guess we can add velocity with particle together, then when it passes solver, it create water volume (surface field and vel field), then why don't we just use pop-source to add particle with velocity?? 3 - There is FLIP solver > particle motion > Droplets > and min/max particle Density. However, there is no density attribute. What density talks about and how they calculate density?? Thanks for reading a lot of questions!!
  3. modify splash in FLIP sim by sink, pump, or pop-nodes

    Thank you, Bunker, for your tips. 1 - It sounds that we don't have so much chance to use pump and sink node operations. 3 - I will use droplet feature to just detect it, and use wrangle to control droplet externally. And, I am still wondering theoretical aspect like a my #1 question. Houdini'd FLIP is designed to modify the both of particles and field together, or just modify one of them.
  4. hi, I have a question about this display function: white water source > visualization > show surface Then blue object shows up. I know this object represent VDB, but I wonder how this tool creates the visualization. I dig into >edit parameter interface, but cannot find any particular trick. At least I found a reference null node inside of the tool. Does anyone know how to create this visualization?
  5. how this "show surface" system work?

    vtrvtr, thank you so much for your reply. I tried your instruction, and my understanding is that it's required to : 1 HDA , not subnet 2 only SOP level I could wish to use it for a SOP subnet, but not avaliable. Anyway, that's good to know where this guide-geo from!
  6. can we get normalized curvature of a volume?

    Hi, LaidlawFX Thanks for your reply. I will write RFE to sidefx, thanks
  7. Hi, I was reading this thread; I checked file "vol_curv.hipnc" and that's great, and I wonder if we can always output a normalized range mostly -1 to 1, probably using voxel size info . I know it could be depends on polygon object and value could not reach max1 or min-1 all the time, but would not exceed -1 ot +1. For instance, it sets vdbfrompolygons1>voxel 0.2, and vdb analysis' curvature shows the range -1 to 10. When it sets voxel size to 0.1, curvature range become -3 to 14, etc. I know, after calculating curvature, we can normalize it by a fit node. But it would be great to output normalized curvature approximately -1 to 1 in all the time, regardless voxel size. Thanks
  8. I recently checked file "vol_curv.hipnc" and that's great, and I wonder if we can always output a normalized value. It would be a range mostly -1 to 1, probably using voxel size info . I know it could be depends on polygon object and value could not reach max1 ot min-1 value. Right now, for instance, it sets vdbfrompolygons1>voxel 0.2, and curvature range -1 to 10. When it sets voxel size to 0.1, curvature range become -3 to 14, etc. I know, after calculating curvature, we can normalize it by fit node. But it would be great to output normalized curvature approximatly -1 to 1 in all the time, regardless voxel size. Thanks
  9. David, thank you for the detail information and I also learned how to use principlecore node, instead of principle shader.
  10. Since new shading system matnetwork came out, do we a method to add AOVs without unlock a default shader, but can create it with combining a kind of layer-shader? If this is possible, it's so easy to add AOVs and no need to unlock shader could save file size, too. For instance, create a material builder and add AOVs like a particle RGB_mask in there, and create a sort of layer-combine shader, then connect the material builder shader and a principle shader into it, then output it to mantra.
  11. I guess you made those nodes and principleCORE in a material builder. In stead of your idea, I was trying to say to combine/mix existing shaders and AOVs under matnet level. Probably my logic won't work..
  12. snow effects with POP grains

    Yeah, I already tweaked a static threshold and scale kinetic. These parameters reduce particle's expansion and push-away. However, it causes more #3's problem, springy and rebounce motion. #2 and #3 problems conflict each other to fix the both.
  13. snow effects with POP grains

    hi, I try to make snow effect with grain solver, started from wet sand shell, wetness=1, and changed clump stiffness to 100. After tweaking around parameters, I got 3 main problems. 1 – how to add friction to static object? I set friction 10, bounce 0 , but particle is still sliding a lot. 2 – When dynamic object collide grain particle, it pushes away too much, but should not influence to surrounding particles. I think constrain pushes away in order to keep space between particles. 3 – particle motion is kind of springy or bouncy. Snow should damp velocity immediately. I guess I need to figure out how to control compression or density of particles by grain's internal constraint?! If anyone knows solutions, it would be great, thanks! grainSnow_v01.hip
  14. David, >>creating your nodes inside materialbuilder VOP for convenient aov workflow. Yes, that's what I plan to do. >>second - I think you never have to unlock the shader to build aovs (at least I've never had to). No. Create, for instance, principledshader, or pyroshader. It's locked. Then I wish to create AOVs not-inside of these shaders.
  15. hi, I tried to use sourceVolume node as dynamics collision. So far, I tried the both of FLIP sim and pyro sim and can see a little bit influence, but it's almost not colliding at all. For instance with FLIP sim, I set: 1 - source volume > initialize > collision. 2 - check binding is correct. 3 - FLIP object > Guides > visualization > collision. I can confirm collision exists in viewpoint. The result looks almost zero collision. I knew this method is not accurate compared to staticObject method, but I could ignore a little lower precision. In fact, it's absolutely NOT acceptable result. On the other hands, when using staticObject, it always works perfect. Is this the exact reason that people combine to use staticObject node for collsionSurface and sourceVolume to add collsionVelocity? In conclusion, Have anyone succeed to use volumeSource as dynamicCollsion? What's differences of colliding mechanism between staticObject and sourceVolume?
  16. Hi, I downloaded the file. I think coding is very hardcore, so will take dummy way. Thank you, Master!!
  17. When creating subnet and putting strings, I want to create auto string's selection like a attached picture. How can I do it for group, primitive, and volume names?
  18. use sourceVolume node as collsion for flip and pyro sim

    Jamesr, I had not been checking this thread, sorry. But yes, I downloaded your hip file and understood input slot well. Thank you so much!!
  19. Hi, I have a question about popAdvectByVolume in popSim. There is a option parameters > update velocity and velocity blend. Instead of blend, I want to add two popAdvectByVolumes, but I have no idea how to use popVop as first picture shows As second picture, I tried to set first popAdvectByVolume as velocity update, and set second one as force update. I was thining two combined vels = vel + force But it's not working exactly. Does anyone have idea how to set up vopPop? thanks!
  20. apply boolean twice problem

    hi, when I try to use a boolean node twice, second boolean result is always broken because I guess a connectivity issue. Houdini cannot understand the connectivity from first boolean result. I know some people says to cut together with many cutters, but I have a certain situation to cut separately. For instance first boolean produces 500 pieces, and keep 300 pieces and use second booleans for other 200 pieces, and so on. Some artist do after-1st-boolean > loop start > delete all pieces(groups) except one favorite piece > do-2nd-boolean > loopEnd > merge together. Or, I do translate and separate each other of pieces in order to make spaces between each pieces, then apply 2nd boolean, and it works I wonder if anyone knows smarter methods, instead of translating or looping booleanTwice.hipnc
  21. use sourceVolume node as collsion for flip and pyro sim

    To jamesr, Yes, I did. That's why I can see correct collsion shape in visualizer. Hopefully someone provides me a collision sample file of either flip or pyro sim...
  22. use sourceVolume node as collsion for flip and pyro sim

    hi, Peon Do you mean VDB surface won't work as collision with sourceVolume node? I tried pyro sim and FLIP sim with sourceVolume node using as static collsion, and I clearly see collision shape by FLIP/pyro object > Guides > visualization > collision, but it's not colliding very well. I guess a visualizer shows the exact collision shape but actual collision sim does not happen.
  23. hi, I have a question about pyroshader in houdini16. There are fire shading and smoke shading parameters separately. That's why I was thinking we could control alpha of fire and smoke separately, too. However, when I change general > smoke > Density Scale value, it influences to fire alpha, too. Then if I set the density scale to zero, actually fire alpha also becomes zero although fire's RGB shows red-yellow color. Thus questions are: 1 - what's the reason/concept we don't have a separate "fire density(alpha) scale" parameter? (Of course, we can separate fire and smoke by AOV with smoke_mask and fire_mask.) 2 - Let's say I need to create a custom shader for it. What kinds of two volume fields should I use for fire and smoke's alphas? Also, inside of pyroshader, there is a pyroshadercore node, which is an essential node but cannot be unlocked.
  24. Because I needed to reformat Windows7, I also reinstalled Houdini, and got strange UI. The node info is broken. Does anyone have thought how to fix? OS, hardware, videocard, and houdini version should be also same as before. I tried houdini 16.0.600,630, 504, but all same result.
  25. apply boolean twice problem

    it sounds boolean node is really designed to use once. Thanks for your tip. I will check it out!
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