To complement our PBD Wire Setup, here is a tutorial on a topic I’ve personally been struggling a lot when I first tried wrapping my head around constraint networks. Similar to what we’ve been doing in PBDs, we’re gonna build a network of interconnecting wires – this time using Houdini’s wire solver.

Disclaimer: I wouldn’t have been able to pull this off without the help of Matt Estela’s CGWiki. Also nowadays we’d most likely use the grain solver (PBDs) to simulate something like the setup shown here. It is usually much quicker without giving much different results. Nevertheless should you run into a situation where you had to use constraint networks – here’s how they work.



Still thinks “Space: 1999” is the coolest thing that ever happened on german TV. Be it pixels, hardware, code or cameras – if it’s interesting, Moritz is gonna take it apart. And sometimes even reassemble it. In his spare time he likes to dabble with code and create generative artwork. He claims his early exposure to QBasic is no help at all when working in Houdini, Cinema 4D, Processing or Arduino. But it might have been what started his fascination for the boundaries of code and art. When not wreaking havoc to any intriguing devices around him, he works as an Art Director at Aixsponza.

More from Moritz Schwind


  • Karel_Dobbelaere 9 months ago  | 

    Hi Manuel,

    tx for the tutorials first off all, they are helping me a lot as this is my first week in houdini.
    this one I can't get to work it seems, I have set up from scratch 2 times checked everything again and again, comparing to the included scene files.
    it keeps falling appart like in the tutorial before you did the debugging, Could it be when you fast forward in the tutorial you checked something trivial you forget to mension? again thank you for this invaluable information!!


    Karel Dobbelaere

    • Karel_Dobbelaere 9 months ago  | 

      Exactly 5 min after I asked the question I found the problem, the anchor_id in the create attributes should be set to integer, I found it after comparing to the suplied scene files.

  • pzpzpzp1 8 months, 2 weeks ago  | 

    Thanks for the tutorial!
    I have a question about collisions.
    You set the collision steps to 1, but if you had set it to much higher would that mean the yarn threads collide with each other?
    Is there a way to check how many yarn threads each thread is colliding with?

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