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ikatz001

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About ikatz001

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    Isaac
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    Mexico City
  1. FLIP sim refraction rendering artifacts

    I have figured out its indeed in the meshing. Somehow the union fluid compress is making major changes on random frames. Its as if when it passes a certain threshold it extrapolates in a different direction and whole internal features of the mesh change from frame to frame in a major way. I've been trying to mess around with it but so far have not been able to solve how to make it give consistent results. Also my compressed particles from where its meshing only have 4 levels of cull bandwidth, which seemed enough at the time. Now im thinking maybe its not, or maybe it has nothing to do with it. Anyone have lots of experience meshing FLIPs that would like to chime in with insight into this problem?
  2. Hi all, I'm getting strange artifacts rendering a flip simulation with the PBR shader set to glass preset. As you can see there are lots of flickering and some features of the mesh even go in and out. If refractions are turned off the problem disappears, however the desired look is no longer achieved. The problem is not present on other presets such as gold, etc. Im guessing this has something to do with how the particlefluidsurface node meshed the sim, being inconsistent with the inner features or something like that. Is this a known issue or something anyone have come across? Can you think of anything to help me resolve it? Thanks in advance, Glass_Test_s.zip
  3. FLIPs Waterline Feature

    Ok thanks for your input. I incorrectly assumed that just because a parameter is keyable it would work in a dynamic sim context.
  4. FLIPs Waterline Feature

    Hey, Nope. I am trying to control where the particles can and cannot escape the tank, via the waterline. (which I understand is supposed to be a new feature in H16 that does just that). Keying the waterline mid sim so you have dynamic control seems to have no effect (as it it is only evaluating at first frame). Any ideas?
  5. FLIPs Waterline Feature

    Hi all, I am using the new waterline feature in flips in H16. It is working fine at first, but I tried to key the waterline to move up during the simulation and it seems to have no effect. The particles still escape even though they are below the waterline. The simulation only respects the initial waterline level and does not move dynamically as its keyed. Is this normal behavior? Any idea what might be causing this and how to properly move the waterline as the simulation advances? Many Thanks.
  6. Using Volume Mask in Particle Fluid Surface

    Hey Karl, Thanks a bunch! That works great. It's surprising its so hard to find how to use that one.. looked everywhere. If you have a minute, can you please explain a little what you did.. I follow the graph, but dont understand - any value greater than zero you convert from an integer to a float and export back to mask? why? Is the volumevopoutput doing anything there is was it just left over from something else? I also had the naming wrong in the fluidsurface node, missing the @name= Im confused when it needs that and when you can just put in the name there like a variable.. I will look more into it.
  7. Hi all, Does anyone know how to use the mask input option to smooth a part of the mesh inside the particle fluid surface node? I want to specify with a volume (ie. a bounding box) which part of the mesh to smooth or keep (instead of using the velocity or vorticity mask). I created the volume to mask with (just a box turned to vdb) as a separate OBJ, I am then object merging it and connecting it to the third input of the fluid surface node, then in the filtering tab in mask input I check it and put in the name of the volume. I have tried to do several different things on the volume itself (regular VDB, Fog VFB, etc.) and nothing seems to work or make any difference. When I turn visualize mask on all it shows is nothing is applied to it (ie. all of the surface has 0 smoothing applied to it) How do I properly use this feature and get the node to recognize the mask? Am I going about this the right way? Many thanks, CrownSplash Anim C.hiplc
  8. Hi all, I am encountering some strange artifacts while rendering a flip sim with mantra. I applied a platinum preset material to the mesh, environment light with HDRI and rendering with Mantra. You can see the artifacts all around the edge of the splash in the video below. I smoothed the final mesh quite a bit on the particlefluidsurface and it helped a bit, but still getting serious artifacts. I also tried remeshing and subdividing as a post process to the mesh it but that introduced new problems where the mesh would look totally unstable. My guess is that it might be doing that because of the constantly changing topology of the mesh? Maybe these meshes were not designed to be rendered with anything but a fluid like shader? Is there anything I can do about it? Attached video and file (using mesh from OUT node in Mesh obj node). Thanks, Top Down Test_1.mp4 CrownSplash Anim.hiplc
  9. Smooth to Faceted Tesselation Effect

    Thanks Ill take a look
  10. Hi all, I am trying to create an effect where I can take any high rez model and smoothly reduce the number of polygons so that it is high rez and smooth on one side, and very low rez and faceted on the other. This is purely for aesthetic purposes, as I think that look would be quite cool. The area where the transition happens should be arbitrary (ie. a group of points) but to keep it simple initially let's just say the transition happens over the entire model on the Y axis, so at the top it has the highest density of triangles and at the bottom the lowest. My initial idea for accomplishing this was simple - put down the model, create an attribute called 'weight' and assign it to points according to their position in Y, then use a Polyreduce with the Attrib Weight set to 1. Alas, this did not work. It reduces the mesh alright, but instead of a smooth transition I get a very sharp transition from smooth to completely faceted. Worse, the keep% parameter doesnt really have much effect on how faceted it is after enabling the weight attribute. Can anyone think of a better way to do this? im sure there is.. Ideally looking for something that could almost be a digital asset and would allow the most flexibility in defining where and how the transition occurs (ie. painting the model, groups, point attributes, etc.) Attached is hip file and screenshot for reference. (p.s. it takes a few min to cook at the current model resolution). Thanks! Smooth to Facet_2.hiplc
  11. Cloth Sim Speed

    Thanks for the answer Marty. I will definitely give this a try. Even though most of my sim is about self collisions and not dynamic forces so I dont know how useful it will be for me. And as I mentioned in the Hforums, I am getting significantly different results in behavior when I change the rez of the mesh (apart from details), what Im looking for is the actual behavior of a high rez mesh. I do wish SES people would work on improving the speed instead of having to resort to these sorts of methods. Thanks in any case
  12. Cloth Sim Speed

    Hi, I have Houdini Indie, I am trying to simulate a cloth animation and am getting very, very slow results. I am doing a simple grid with 100 by 100 res fall into a smaller cube. On the default Finite Element Solver settings it is taking close to a minute per frame. If I increase the res of my mesh to 300 by 300 it gets close to 12 min per frame (I am running dual high end xeons, 256GB RAM, Quadro4200 and Tesla K40c). I am not even seeing good CPU utilization hovering between 9 and 12% I tried to disable substepping and setting the Max Iterations Linear Solve to 128 but it barely has any effect. Is this normal behavior or can I assume something is wrong?? Thanks,
  13. Houdini Cloth - Unbelievably SLOW!

    I'm wandering the same thing. Just started doing some cloth sims on H14 and was irritated and confused at the amount of time it was taking. I even thought maybe I was doing something wrong until I read this forum topic. Any word from SESI people on what the status on this is??
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