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KarlRichter last won the day on June 14

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  1. Grains - how to make 'em bounce off surfaces

    Look closer. I know it seems like setting ispbd to 0 would disable the grains entirely, but it doesn't! The particles bounce, but still maintain distance. It's hard to see in your test scene so I made one that illustrates this better. ispbd_test.hipnc The ispdb flag does not disable grains, it is there to tell the pop solver that a given particle is under control of pdb, so don't apply all the regular pop physics. Indecently, before I was aware of this flag I would fake a bounce by giving each particle a random upward velocity on the first impact.
  2. Grains - how to make 'em bounce off surfaces

    Set the attribute "ispbd" to 0. See attached. collision_grains_v02.hipnc
  3. Bee Movement

    Here is a quick example of how you could achieve this kind of effect with the grain solver. If you wanted to get fancy with this, you could constrain pairs of grains together to more accurately represent the bee body shape. bees.hip
  4. 2D vellum Simulation

    If you use a sop solver to explicitly set the y point values of the cloth geo and an additional sop solver to do the same to the constraint geo, you can very effectively constrain your sim to just two axis. See attached for example. BTW, it may seem that you only need to manipulate the "Geometry" data, and in the simple attached demo that seems to work fine, however I have found that with complex vellum sims you really need to run over the "ConstraintGeometry" data as well. vallum_x_constraint.hip
  5. HTOA missing shaders in new versions

    The Arnold shaders are under "shading", but the "skin_SSS" shader has been deprecated as of Arnold 5:
  6. Here is an example using rest fields to drive displacement for the purpose of adding detail to a smoke sim, but it could be used for any kind of displacement. There is an example .hip in the Vimeo description.
  7. cloth capture weights

    Is there really no (easy) way to edit the weights generated by the "cloth capture" sop, or am I totally missing something? It seems like the "edit capture weights" shelf tool should do it, but I guess it's for bone weights only. Kind of a big omission, especially with the the addition of the new Vellum stuff. What is the solution to transfer a low res cloth sim to a hi res asset? I am currently getting ok results with the point deformer, better then with the cloth deformer, but it would be really nice to adjust weights on a more granular level. I have been comparing the results between the new vellum cloth and Mayas ncloth for use in an upcoming project. While I have been getting pretty good (and fast!) sims with vellum, I have been having issues finding a reliable way to transfer the sim to the render asset.
  8. calm flip water in custom conteiner

    Here is a simple setup that gets your pool very still by damping the vel field in your pre-roll puddle_testt_v02.hip
  9. This excellent tutorial will help you solve your orient issue:
  10. Wire constrained to two objects

    Here is one way to do it using wire constraints. See attached. wire_constraint_example.hip
  11. Some FLIP questions

    Rather than directly answering your questions, I would suggest pursuing a deeper understanding of FLIP fluids. I highly recommend this masterclass, it really opened my eyes:
  12. FLIP Energy transfer?

    Ahh... For non-Newtonian you may want to look at pressure. You can turn the pressure field into a particle attribute by using the "gas field to particle" gas microsolver. Then use that to drive the viscosity or something. See attached for a quick example. pressure.hip
  13. FLIP Energy transfer?

    That would probably work, although I have found the POP collision node to be unreliable with FLIP if your particle count is changing rapidly (like if you have reseed on). You may consider using a sop solver with the "xyz distance" node to make your own collision detection.
  14. FLIP Energy transfer?

    If you subtract the velocity of the previous frame from the current frame, that would give you the direction and magnitude of the "force" that affected your sim that frame.
  15. Fire Sim

    @jurueta benne5 has the right idea. When I need to make a pyro sim go "faster" I use a combination of the solver time scale and the dopnet time scale. The dopnet time scale can make the biggest difference, I have found, but you must also increase the substeps on the pyro solver the proportional amount. Also, when simulating fast moving fluids, i always set my min and max solver substeps to the same value. In your example scene, I was able to make your flames go very fast by setting the dop time scale to 3, and the min and max substeps to 8.