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art3mis last won the day on October 7 2018

art3mis had the most liked content!

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About art3mis

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    film making, cinematography, unity 3d, motion graphics, VR
  1. Any Object CHOP users? Trying to understand how I might use to rotate a sphere using a point on the sphere defined by a 3D Cartesian coordinate x,y,z feeding into the xyz Target input.
  2. This is more of a general math question I think and doesn't just pertain to Houdini. Given a set of Long, Lat coordinates I need to rotate a sphere which represents the earth. What would be the general logic to solve this? I know it involves Cartesian to Spherical coordinate translation but that's about it.
  3. Yes the Volume Tab. AFAIK for a Spot light its the only place you can enter Samples.
  4. OP Edited post to include 2 images. Getting a lot of noise and fireflies in the reflections. Again 2 dome lights 1 volumetric spot with 1024 samples ray contribution Uniform Settings 16 min 512 max Adaptive error .01 Sample Filtering Gaussian 2,4,4 GI disabled.
  5. Thanks. Will try and post a higher res frame once I am closer to completion. So I assume no need for GI?
  6. Any CHOPs experts? How do you enable MotionFX but only to start at a specific(current) frame? Simply keyframing in the main timeline doesn't work.
  7. Created kind of a render torture test. All that is missing is caustics! Would appreciate some expert RS feedback on some starting settings to try for a quality render. Assume I will be enabling motion blur on the water droplets as well. In this simple scene are there any advantages to setting samples at the Material level (water, glass)? Using 2 Dome Lights, a Volumetric Spot and slight accent with backlight area. glass_water_volumetric.mp4
  8. Thanks. I am using the proxy volume so I guess I am ok.
  9. So used Collision separation override but still have issue. Through trial and error though I think I am getting closer to figuring out why. In 2 tests with the exact same settings, the only thing I changed was the Collision Separation override on my FLIP Object. When it was set to .5 * Particle Separation the simulation fails at around frame 100.(the particles rapidly drain away) When it was set to .25 * Particle Separation the simulation fails on or around frame 40. I checked and OpenCL is NOT enabled on my Solver. The issue seems to go away when I have a coarse Particle Separation of .05 or more. What else could be causing this? Is this possibly memory related?? Launchv12__FLIP_Failure025ps.mp4
  10. Thanks. Will try enabling Collision Separation override and using ch("particlesep")*.5 as a start.
  11. Thanks. Still gaps in my full understanding of FLIP but wouldn't decoupling in this way mean that your collision resolution would be 'coarser' than the particle separation and make the issue worse? Just to clarify I've created a custom Voxel Size parameter on my Flip Object which is a product of Particle Separation * Grid Scale It is this custom Voxel Size parameter I am linking to on my Collision Source SOP>Volume>Voxel Size The problem seems to happen when I increase my resolution (reduce particle separation and hence voxel size).
  12. AFAIK the ONLY difference in the 2 attached simulations is that in the 'failed' one I have simply reduced my particle Separation from .05 to .025. In each case the resolution of my collision VDBs is directly tied to this resolution. WTF is happening? What should I try to fix this? I need the increased resolution. Pulling my hair out. Launchv11_025ps.mp4 Launchv8_05ps.mp4
  13. Question about proper way to animate your geometry when using for collision. If you animate some geometry and then use an Object Merge to bring this geometry inside another geo where you create your collisions (using either Collision SOP or VDB From Polygons) ,does this mean in essence you are recreating your collision VDBs on every frame? AFAIK the important thing is that your collision VDBs contain correct velocity values.
  14. Proper scale for FLIP

    So this has been mentioned in a few other threads but need some guidelines. My understanding is that FLIP has issues (unstable, flickering, collision, etc) for "small" scale simulations. By that I assume means anything under roughly a metre in largest dimension. What are some suggested starting points for scaling up your simulation for FLIP if its say, roughly a foot or so in diameter. 3X? 10 X? And what about speed to compensate. If you increase the scale 3X do you also need to speed it up 3x as well? There is also Spatial Scale on Solver and was wondering as a first step if i should try reducing to say .1 before I do anything else?