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Posts posted by Pazuzu

  1. 12 minutes ago, Andrea said:


    How many particles there are in total? Each drop looks like has around a hundreds if not a thousand of particles inside

    Thanks Andrea!

    Attached are two screens where you can see the general particle count. I tend to not abuse the particle count to have good meshing results (so I don't use re-seeding), that's mainly because if you need to re-time you can have weird pulsing artifacts, so the only way to overcome this is to over-smooth, and that can be very expensive sometimes and will kill nice details, also boundary conditions can have flickering as well with overcrowded particle clusters closer to colliders. Instead of this I use a method to redistribute the particles to have a more uniform distribution between them, this way you can have very nice and smooth edges without so many particles and have a more clean and smooth mesh without sacrificing details. 



    • Like 3

  2. Hi,

    Here is a personal project that uses a new iteration of my small scale pipeline. I still need to improve some things regards the micro-ripples but I think they are working well for this one.

    I hope you like it!



    • Like 8

  3. 6 minutes ago, tylerafx said:

    Now we are talking! Impressive.. definitely need the ripples to travel a tad more, yet you can see they dont affect the dynamics as much. How about air influence and bubbles/airentrapments? is that in the cards?


    Yes, the ripples on this mesh test are just a post process, so there is no direct relation with the sim; That's why it still needs improvements. Regards air influence I have some options already, that's why the sheets breaks also, is like when you have a cloth and because of the drag mechanic's you can affect how it will fly relative to his shape against the wind, same should happen with a fluid sheet but the influence is a bit different, but this will lead to a more natural look regards sheet breaking. Finally bubbles and trapped air, this one is more artistic driven, I did some tests some years ago with a very viscous fluid ( https://vimeo.com/69638111 ), but was just using fake rules to populate them; But that is also in my to do list, like I said the wind or environment is so important for this kind of details, for bubbles is a combination of pressure, vorticity and wind/environment interaction, or maybe I'm wrong, its all about to experiment than to find a "Physical correct" way of doing things. :)




  4. @tylerafx Here is the update I was talking about. The mesh still needs to improve, but this is just to show the tool's update/fixes that I did on my pipeline to get rid of the volume issues and overshooting mainly to have a more natural sheet breaking and wobbling.

    I hope you like it!




    • Like 3
    • Sad 1

  5. 1 hour ago, tylerafx said:

    Alejandro, is there any update to your Asset yet? Latest tests looked stunning for sure, but some areas could be improved still, right?



    Yes I have some updates going on. Unfortunately I can't post them. But which areas do you think it needs to improve? It will be nice to discuss about it.

    One thing that I was working on was the velocity overshooting issue, So the contractions of sheets was not behaving right in terms of rate and volume preservation, this issue is visible in the latetest test I posted in this forum topic. I fixed that already in my last iteration, I'll try to post some results soon.

    Thank you!


  6. 4 hours ago, gramx said:


    Loving the speed of the new sparse solver in Houdini 18. I have a job where I have a medium res simulation and I need to upres it for final render without the motion changing to much. I would usually use the Up-Res shelf tool to set this up, but have found it doesn't accept the sparse solver as a source. Is it possible to manually set these up, has anyone tried it?



    Hey Graham!

    I think is all about to update the up-rez pipeline to make it sparse. I think is not that hard to do it!



  7. Regards speed, I think it mainly depends on the method, but the vdb one is the best in terms of control, because you can continue to filter and reshape the field using the vdb arsenal. Sometimes the gas reinitializesdf microsolver is faster, but it can also become a weird bottle neck with huge boundaries, for example if you want to compute a gradient out of an sdf and you need the gradient to cover the whole volume container or to have a better extrapolation, in this case vdb can be a pain because of his sparse nature, of course you can expand or extrapolate your sdf using the amazing vdbactivatesdf, but that can be even slower than to use the microsolver directly.

    • Like 1

  8. I think is also because of the details. I assume this is a small scale thing, right? If so, you should use surface tension, right now it looks like a large scale one with lack of splashing detail, if you want more detail at large scale try to use the "swirly kernel" on the solver, this will preserve even more the momentum of the sim but will smooth a bit the violence and chaos behavior in comparison with the "splashing kernel", but will give you much better splashing details.

    Then on the skinning stage, you can try an old school method: with a VDB pipeline use: Dilate - Smooth - Erode. 




    • Thanks 1

  9. 14 minutes ago, scorpes said:

    Really nice Pazuzu! How do you create the individual droplets coming from the crown, is that a separate particle emission?



    Thanks for the comment!

    Its part of the same simulation. That WIP shows a new option functionality of my small scale pipeline to control how much do you want the droplets to detach from the main fluid body. Its a very important artistic control in a simulation.



  10. This video will give you very good foundations on using the pop fluid! That way you don't need to "Abuse" anymore curvature on FLIP method to have "Beautiful" crown splashes!! ;)



    • Like 1

  11. 5 hours ago, moneitor said:

    Brutal viejo alejo, yo tengo ganas de hacer un ripple parecido para deformaciones de metal a gran escala, pero seguramente lo hare como un postproceso.

    Gracias viejo Hernan! Para eso hay una muy buena referencia, y podrias hacerlo si quieres de esta forma, el problema esque necesitarias tets (seria deformarlos de cierta forma para asi enganhar el tool ya que no salen directamente de FEM) y lastimosamente es una pesadilla en cierta geometria, pero creo que vale la pena pillarlo! Aqui te dejo un link:




  12. 27 minutes ago, HowardM said:

    Thanks everyone, cool stuff!  Great shading on your last render Pazuzu!  Mind checking your messages?  Cheers!


    Hey Howard! Sorry about that! Here is the scene, I polyreduced a bit one of the frames of the sim to have a less heavy file to share!

    By the way, that mesh still has a freeSurface attribute; So you can use that gradient for nice shading effects.

    I forgot to say that this scene uses Redshift. v2.6.32; H17.459.




    • Like 4

  13. 6 minutes ago, moneitor said:

    Hey man, great job, are those micro ripples in the simulation itself, or you are exporting attributes to drive them in the meshing stage?

    Hablame en espanhol viejo Hernan, por lo menos pa que practique!! :)

    Estoy usando el gradiente del atributo que genero dentro de la simulacion para detectar el FreeSurface; Los MircroRipples en este preview son calculados en simulacion, pero a veces no se contrastan lo suficiente asi que los contrasto a nivel de mesh tambien para que se noten mas aun, ya que al rasterizar las particulas se pierden si no se usa una resulucion muy alta, por ende opte tambien en tener una solucion que no necesite resoluciones muy altas para hacerlos mas notorios.

    En este preview podes notarlos directamente en las particulas!


    /,,/ /,,/


  14. 6 minutes ago, Atom said:

    Nice work, does this make use of the new H17 retime node?

    Thanks Atom!

    For this retime I used an old tool that I developed years ago to do almost the same as the new retime tool, the main differences are the nice interpolation options for attributes that the new H17 one has, mine just have linear as interpolation option, so I'll migrate very soon to that one.


  15. Here is another test using a last iteration of my tools to do small scale stuff. This time, now is possible to art direct how much do you want to break a sheet into drops and tendrils, and there are some Micro Ripples on the sheets that are relative to the fluid speed and curvature at some portions of the main fluid body!


    Thank you!


    • Like 3

  16. 2 hours ago, Jesper Rahlff said:

    big question for me would be if Vray is still faster rendering volumes.. Not sure it would be. Mantra is not doing to bad when it comes to volumes

    I think Mantra is faster when rendering volumes, but the main issue is when you need multiple-scatter; Right now the path tracing alternative to point clouds is extremely slow in comparison with Arnold for example. Lets hope that H17 surprise us with some improvements for Mantra in volumetric rendering.

  17. 3 minutes ago, toadstorm said:

    It's actually possible to use op:/ syntax to point at SOPs in a shader, as long as the SOP is the output (or upstream of the output) of an object listed on the Mantra ROP. If you don't actually want that object to render, you can add the vm_renderable flag to the container and set the value to 0.

    Yeah I know! I was meaning that not directly, you need to tweak first to make it functional. Even when you tried to render that's what the command line tells you! I didn't explain my self correctly! :)

    • Like 1