Houdini In Five Minutes 09: For-Loops & Extrusions

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Part of: Houdini in Five Minutes
Houdini In Five Minutes

Apart from attributes, loops and iterative techniques are maybe the most useful concept when building your procedural geometry inside Houdini. With very efficient node trees we can cook up pretty intricate effects.

NOTE: As I might have mentioned, Mantra is by no means a fast render engine, so I decided to render out the preview images in this video using Octane. If you want to learn more about rendering in general and using third party render engines in Houdini, you might want to check out our premium course on rendering… 🙂

Download Project File

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  1. Really enjoyed this, and learned a lot this evening.

    Can you explain why `@iteration` isn’t a good choice for Global Seed values (on the surface it seems like a more efficient and simple expression than `detail(“../repeat_begin1_metadata1/”, “iteration”, 0)`.

    • Heyhey,

      with @iteration you’d access an attribute on the geo stream itself. As the loop’s metadata node isn’t conected to the geo stream (no wire going through/into it), there is no attribute called “iteration” on the stream itself. So with @iteration you’d not be able to read in a changing iteration number. That’s why you’ll have to rely on the slightly more complex detail() function to access another node’s attributes.

      Cheers, Mo

  2. What’s super disappointing about your stuff is that you never really follow through, meaning the clickbait rendering that makes people watch, is most times not the outcome of the video! No more Patreon support from me…

    • Hi Miguel,

      sorry that Entagma is not for you. We focus on one topic in our tutorials, the finishing work is intentionally left up to you. We’re trying to communicate underlying principles, not providing ready mix recipes. Also you’ll find a render setup in the download.

      Thank you for your constructive feedback, we value your input.
      Manu & Mo

  3. Hello! i was following your tutorials since november 2019, they are awesome!

    I have a question, how did you made the extrusion go in the axis so long? maybe with a if and making the first iterations more large than the last? is there a way to make it more automatic?

    • Hi Rodrigo,

      good question. Have a look at the render file we provided in the .zip – there you can find the exact setup. In this case it’s a mathematical expression taking care of the scaling 🙂

      Cheers, Mo

  4. your tutorials als simply incredible! so much fun – and the pace is great, even for somebody totally new to 3d software (such as me). a real motivation to get out of bed during the current state of affairs 🙂

    • Ciara@Entagma

      Really glad to hear that you’ve found them helpful, thanks for your support!

  5. Chandi Campbell

    Hi and thank you for your tutorials! They have helped me so much. Hitting a snag on this one though. When I enter “@active == 1” in the group field of the PolyExtrude, it is not pulling a random value from the distribution in the AttributeRandomize but rather a face value. The only face that gets extruded is Face #1. It’s as if the “@active” is being ignored. Any suggestions?

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