There are many ways to move millions of points in Houdini. Usually, quickier one is to make static velocity fields and move all points through it. But my approach is to make fields with Pyro, which also driven by particles, to have more control on how fluids are moving. Then move all the points through Pyro velocities, with possible mixing with other sources.


Let’s take a look at a first example.


1. Simple particle setup making a swirl.

2. Previously made points are passed to Pyro for more interesting liquids dynamics. In this case, I used 2d fluid grid which works much quicker.

3. Velocities from Pyro advected big count of points.

Simming with wedge

Wedge in Houdini is like partitions in Krakatoa. It allows splitting particles saving into smaller chunks, which greatly reduce simming time. In my case wedge changes only particles seed, so setup is simplified as possible.

To make full quality renders like in examples. Just go to ropnet1_simming and run wedge1. After that load all partitions in 4_RENDER_PRTCL_CACHES and you’re ready to render final image sequence with ropnet2_render.

I will update this post with more examples, including Flip Fluids experiments. Meanwhile, follow my Instagram or Facebook for the updates.

10 Responses to “Houdini oil in water”

  1. Wuyang Wang, Reply

    This is Awesome Man! Thank you so much

  2. Blain Klitzke, Reply

    Very beautiful results. Thank you!

  3. Orlando Fernando Marconi, Reply

    I open the file and it tells me that it is missing PR parameters, how do I solve this?

    • deko, Reply

      Maybe you have older Houdini version? I made this with 16.5.323, but should work in newer versions as well.

  4. fusion_bsc, Reply

    Man, that is awesome, thanks a lot. Houdini is a monster of a software! One question though one round of wedge took almost 40 Gigs of HD.
    Your example is set to 20 times that – almost a TB of disk space – is that right or am I doing something wrong.

    Anyway – your content is fanstastic! Keep it up.

  5. fusion_bsc, Reply

    Awesome stuff, man! Keep it up.
    One round of wedge took around 40 GB of space – is that correct? Seems that all 20 wedges will take almost 1 TB of space, kinda heavy.

    • deko, Reply

      That’s correct. Wedges count isn’t required to have so many, you can have a pretty decent result with less.
      Also, file sizes depend on which data you’re saving. If you don’t need velocity or age/lifespan, you can easily remove them from saving. In my situation, I leave them to have more coloring ability after caching.

  6. Terry, Reply

    The secd download hip is jpg… instead of hip file :D

  7. Anonymous, Reply

    Amazing and very pretty results!

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