Procedural Stream 1: Geometry and UVs

Welcome to this tutorial series about creating a procedural stream with flowmaps in Houdini. You can find all the scene files and more tutorials on our site. 

This is the 1st out of 3 tutorials, focussing on the generation of a small, procedural stream. In part 1 we create the terrain, generate the river and create our start on the flowmaps data!

This is the 2nd tutorial of the Procedural Stream series, focussing on the generation of a small, procedural stream. In this part we dive into Unreal and get our flowmaps and materials to all work together in a single HDA (Houdini Digital Asset)!

Currently we are looking at all the feedback and ideas and because of the changes with the flowmaps in H17.0 and H17.5, we will postponing part 3 of this series for now. We will look over part 1 and 2 and probably make a complete remake of this series in the future! Make sure to keep track of what we are doing.
   - Cheers! ;-)



As the original founder of Dokai, Ivo is passionate about using Houdini to create procedural content for cinematics and videogames, and is currently working as a Technical Artist on the new Gran Turismo games for Polyphony Digital at SONY Interactive Entertainment with the focus on Environmental design. He graduated from IGAD (International Games Architecture & Design) in Breda with 3 years of experience with Houdini, and loves environmental design. He also interned at SideFX Software‘s game dev team in 2018/2019.He grew up in Tilburg, The Netherlands, is an avid martial artist, and wants to help you with his knowledge and share his experience from the industry through tutorials and seminars!

More from Ivo van Roij


  • McKormick 2 years, 5 months ago  | 

    Really nice tutorial, however the way you adapted a river to the terrain causes the issue that river flows up the hill which is physically incorrect.
    I'd love to see solution to that, sth like checking Y position of previous point of river curve and adjust the current one based on that check - just to make sure water always flows down the hill.

    • Ivo van Roij 2 years, 5 months ago  | 


      Thanks for your reply! We know that creating rivers and streams usually adhere to a physically correct downhill stream, however, that was not the purpose of this tutorial. The main goal was to show you guys how to create a stream, how to combine geometry, average normals and create some procedural flowmaps, all in one HDA! This gives the end-user (we'd assume a designer or artist) the control to draw the curve down the slope they intent it to flow down to. Automatically calculating it so water doesn't flow uphill will either A) ruin the flowmaps, as you'll have inverse velocity on certain parts, which messes up the feel in the game or B) takes away control from the artist to make it flow in a certain direction, whether up or downstream. Thanks again for watching and who knows, we might actually bring out a tutorial on our Patreon eventually that shows our solution to that problem!


  • corylynch13 2 years, 5 months ago  | 

    I noticed when you went to change the height to a default value, you changed the width, to 0.3 also when I copy the game baker, then paste it to the ROP it says that speccolor doesn't exist and it fails to create any flow map.tga because of it

    • Ivo van Roij 2 years, 5 months ago  | 


      Thanks for the reply, it's nice to see people point out specific parts of the tutorial series. The problem of your speccolor might be related to the paths inside of the Gamesbaker. You can try 1.60 (now called GameDev Games Baker) or make the content editable and dive into the paths to make them all relative (/Gamesbaker/objnet/low/objectmerge etc. etc.). I'm currently working with the (eventually) upcoming H17.5, and because I have multiple versions of both Engine, Houdini and other software installed, I'm getting a few errors around. When I've cleaned up my machine next month, I will probably re-record this and the 3rd part of this series and make sure that the errors you're running into aren't in them. Thanks again for watching and giving some feedback!


  • Novae 2 years, 5 months ago  | 

    Thanks for the tutorial. You mention Part 3, but there is no Part 3 on here, or on your website. Did you decide not to do one?


    • Ivo van Roij 2 years, 5 months ago  | 


      Part 3 will come out soon, I still have to record that one! Don’t worry, it will definitely come out soon ;-)

      Kind regards!

  • muxalko 1 year, 7 months ago  | 

    Thanks a lot for such a wonderful tutorial!
    However, I have an issue with the "Recalculate Flowmap" button. It's just not working from UE.
    When I tried to load the scene in houdini, the same button didn't fire until I unlock the HDA (Allow Editing of Content).
    Then' the button works as expected.
    Do you know why might that happen ?

    Waiting for part 3 !:)

    • Ivo van Roij 1 year, 6 months ago  | 


      Thanks for giving this tutorial extra views haha. We will be completly remaking this in H18, as a 4 part tutorial series. Keep an eye out for our tutorials on the Dokai website for more info!


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