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Everything posted by Pazuzu

  1. FLIP smorganic/sheeter effect?

    Hi Sebastian! You're welcome! About the values, it mainly depends on what you want, for that example file that value works well. Its pretty high because the resultant gradient has very low magnitude. Remember that this file is just a template, a very rough template, so much to refine still! Cheers!!
  2. Very Nice Stephen!!! Thank you!
  3. FLIP smorganic/sheeter effect?

    Hey Guys!! Here is a video that shows a very fast and simple surface Tension Method! There is also an example file for you to inspect the method! Thank you!
  4. Advanced Math for Houdini

    Hi Petz! Nice answer about maths! I'm fan of your explanations and example files here on OdForce! But what about dissecting some siggraph papers for example (computer graphics research), I think one needs better understanding of deep maths to implement those algorithms, no? so again the question, what kind of maths or level of understanding do you need to dissect those computer graphics papers? I know some calculus, linear algebra, etc; But sometimes there is very deep math in those papers, like some Russian vodka of maths! So difficult to understand and implement. Thank you!
  5. H16 at Siggraph?

    Ohh I really want to test the new surface tension model! I hope also some OpenCL news on this version (wranglers), and the most important thing, a robust subversion system for assets (GIT, :)). Cheers!
  6. Grains restlength vs constraint length

    jejejejej Todo Bien!! Saludos!!
  7. Grains restlength vs constraint length

    Because constraints are just polylines between points you can use the nearpoint o neighbors vex functions to iterate through the points you want to compare the distances (modo chambon ), or you can already use the arrays created internally by the grains solver (way faster). Then if you want to manually break a constraint, you can just set your weight attribute for the constraint. Hope that this helps! Saludos!
  8. VDB Analysis (Laplacian, Divergence)

    Hey Diego! Sure! Here is a very basic FLIP surface tension implementation using laplacian as a factor; You can change from Laplacian to Curvature to see some little differences, But for most cases Laplacian works better for my tests, and even better yet for smoke, as you can see in the example file, the FLIP sim behaves almost like a pyroclastic cloud at the begining, so imagine this in a gas sim. Hope That Helps! Alejandro ST_tutorial.hip
  9. VDB Analysis (Laplacian, Divergence)

    I usually use laplacian as a factor of perturbation in a smoke or FLIP sim, so you compute the laplacian (curvature has also a very close effect as with laplacian) of your surface field + a gradient to displace your particles for example. In the case of a smoke sim, I drive the divergence with the laplacian, so you can get nice bulbs without the use of vorticles or custom particles solutions to perturb the vel field. Hope that helps! Alejandro
  10. Random link of interest

    Today the procedural generation is begin to emerge as an standard for space sandbox games, but this franchise was one of the first in 1984 (Hail to David Braben): https://www.elitedangerous.com/
  11. Houdini reaction diffusion

    This "Human" behavior is so normal nowadays!! Its a real shame, when I see posts like this, begin for a .hip file without pity. Sometimes I really miss the old community!
  12. Forum upgrade

    Thank you very much Marc!! All Looks awesome!
  13. Cube3 - A short film.

    Very Nice Work!!
  14. point clouds and vex

    Hi! Just sample the handle inside your condition and all works! float radius = ch("radius"); int npts = chi("numpts"); int handle; if (@side > 0) { handle = pcopen(@OpInput2,"P",@P,radius,npts); v@Cd = pcimportbyidxv(handle,"Cd", 0); i@num = pcnumfound(handle); } else { handle = pcopen(@OpInput3,"P",@P,radius,npts); v@Cd = pcimportbyidxv(handle,"Cd", 0); i@num = pcnumfound(handle); } pcclose(handle);
  15. FLIP smorganic/sheeter effect?

    Thank You Guys!!
  16. FLIP smorganic/sheeter effect?

    Hi!! Here is another update for the Tension asset! I hope you like it! Thank you!
  17. Nice solution as always!!
  18. Hi! Not the most elegant way but works! Cheers! padding.hip
  19. Layered Ocean Evaluations

    Hi! Because the ocean spectrum node gives volume primitives with frequency and amplitude information to ocean evaluate, you can use a volume mix node (experiment with the blending modes) between two ocean spectrum nodes with different settings, then just connect the output to the ocean evaluate and voila! You can try also a texture compositing approach, its way more versatile, because you can tweak (distort, offset, invert, etc) also the uv coordinates for nice blending effects. Hope that helps! Cheers!
  20. FLIP smorganic/sheeter effect?

    Thank you! Here are some more tests to compare the new APIC method (swirly kernel) in the FLIP solver for H15 with the default one (splashy kernel) without hole filling approach; In those tests you can see a mask attribute as visualization, this attribute controls the weight or influence for the cohesion that controls the behavior, so red area is where full energy is apply to minimize the surface area leading to spherical shapes. https://en.wikipedia.org/wiki/Surface_tension Also a chocolate like sim to test the pipeline in viscous fluids and with a standard meshing stage. Hope you like it! Alejandro splashyKernel.avi SwirlyKernel.avi preview_v004.mov
  21. FLIP smorganic/sheeter effect?

    Hi Strob! The Vosilob asset uses surface tension based on curvature decimation, so you compute the curvature and gradient of your surface field and use the two fields to push and pull in convex and concave zones, so the particle field tends to form drops and shape in nice forms. I'm using a different approach to this, I combine the curvature decimation technique with more additional custom forces and PBD based approach; So you got nice drops, tendrils, uniform distribution, and more volume conservation control; About a "fill hole" approach, I don't use a direct particle filling method mainly because of the volume gain, it woks in some scenarios but in some is not so practical, also all the particle field tends to grow and shape in a very thicker way; So for the hole filling problem I'm using a field based approach with some force, frame and pressure conditionals to control the volume gain and thickness, but this is still WIP, I'm just developing this at free time. I hope this helps! Alejandro microTension_v1.5.avi
  22. Hi, Look at this post! http://forums.odforce.net/topic/23004-mask-surface-tension/ Hope that helps! Cheers!
  23. Hi!! Here is my last research about small scale sims with the FLIP/PIC method, I hope you like it! Thank You!!
  24. Hola Arturo! La implementacion mas basica de tension superficial es calcular la curvatura de la superficie del fluido (en el caso de FLIP, el "surface field") para luego usarla como factor de desplazamiento usando el gradiente (normal) de la superficie del fluido. As que si la curvatura es negativa (concava) la fuerza se ejercera hacia afuera, y si es positiva (convexa) la fuerza se ejercera hacia adentro, de esta forma a medida que el sistema avanze frame a frame todo intentara forjarse de forma esferica debido a la decimacion por curvatura, dando como resultado el efecto deseado. Saludos!