In this lesson, you will learn how to create a functioning door asset that can be used to rapidly add doors to a level. Each of the doors will be consistent with the design aesthetic of the level, while allowing your designers to customize the shape, size and detailing on a door to door basis. One asset built this way can generate multiple doors in the Unity editor that are all game-ready with efficient poly counts, uvs, collision geometry and texture maps.

You will start by creating a procedural model in Houdini then you will set it up as a digital asset that can be opened up in Unity using the Houdini Engine plug-in. The asset will generate both high res and low res geometry which will feed baking tools built right inside the asset. These will create texture maps that can be used in Unity to feed a shader that can be customized for each door. You will then reference a script so that each door is automatically set up to control the opening and closing of the door based on trigger geometry.

NOTE: This lesson uses the Quick Groups and Sci-fi Surface Detail assets which are included with the project files directory. Please take these and put them in your home directory in an otls directory (which may or may not already exist). This way the assets will be available for your Houdini sessions and your Unity sessions when you are working with the Sci Fi Door Asset.


Before you build the asset, this video will show you the finished tool to give you an idea of what you are trying to accomplish. You will see the tool in action inside the Unity editor then take a quick tour of the node networks in the Houdini scene file. 

Length: 07:07


Most game artists can model a door like this easily but making many of them for a game can become repetitive. In this lesson, you will learn how to work procedurally in Houdini to create a system that can be used to generate different doors with unique sizes and surface details. 

Length: 36:59


In order to share your procedural Houdini setup with level designers in Unity, it is important to wrap up the node network into a Houdini Digital Asset [HDA] which can be loaded into Unity using the Houdini Engine plug-in. You will load the asset early in the process so you can see how each step taken to build the UI of the asset affects how you use it in the editor. 

Length: 28:30


To create game-ready art, you will prepare high resolution and low resolution geometry which can then be used to bake out textures. You will also use curvature and occlusion to find areas where you can add dirt maps. These get baked out too and will be used in the next lesson to create the final shader. 

Length: 27:56


Now that you have the model in Unity and the geometry baked out, you can use the generated texture maps to build a Unity material. This material can be set up in the Houdini network so that it is picked up automatically by the asset. You will use a similar technique to add a script to the asset designed to open and close the door when collision triggers are set off. 

Length: 22:46



Simon is a tech Artist that loves building procedural tools and assets. By adding more and more procedural approaches to his workflow, he is able to build 3D models with speed and flexibility. During his studies at Digital Arts and Entertainment, he taught himself how to work with Houdini. After his studies, he started working on Ary and the Secret of Seasons at eXiin. Currently he is a Houdini freelancer and focuses on creating procedural content.

More from Simon Verstraete


  • Ivo van Roij 1 week, 2 days ago  | 

    Hele gave dingen Simon! Top om te zien en een inspiratie!

    • Siver 1 week, 1 day ago  | 

      Dank u :)

  • teotigraphixllc 1 week, 1 day ago  | 

    Kickin them out!, nice job man.

  • MaxDFr 1 week, 1 day ago  | 

    I can't found the quick group and sci-fi surface detail HDA in project files, only a sci-fi door tutorial but I don't know how to extract them

    • MaxDFr 1 week, 1 day ago  | 

      curiosity offer me a solution ;)

      • MaxDFr 1 week, 1 day ago  | 

        But still a problem : This node is using an incomplete asset definition. It will not function properly until the asset library containing the full definition is installed.
        And I ignore what to do.

        • Siver 1 week, 1 day ago  | 

          We are currently looking at it. What you can do is place the HDA files in where you installed Houdini (Like: C:/Program Files/Houdini18 ).
          In the folder look for a Houdini folder in the Houdini folder you should find another folder called otls. In this otls folder place the HDA files.
          Restart Houdini and Unity if they are open and once restarted check if the HDA is working.

          • MaxDFr 1 week ago  | 

            not solved, I make all you wrote but it's not working on my 17.5 version, so I dowload the 18, make instruction again, but i'ts still not working.
            and to be sure restart my computer and no change.
            If you have a tutorial for create these HDA, I'm in.
            and thanks for your time.

            • Siver 1 week ago  | 

              If you type "quick groups" or "sci-fi surface detail" in Houdini 18, you can't see them, right?
              So then they are not installed correctly. So first of all you can download them on this page at the top then place them in the documents folder and search for Houdini18.0 and then place them in the otls folder (create a folder named otls, if it isn't there).
              Restart Houdini, do you see them now in Houdini if you search for them?

              • MaxDFr 1 week ago  | 

                Thanks a lot, it's working know, but you change files or I'm totaly blind ?
                thanks for your time again.

                • MaxDFr 5 days, 22 hours ago  | 

                  I've a last question, I use Unreal, but in your tuto you use Unity, your hda are good for unreal too ?
                  Cause I realy want to finish your fascinating tuto but I'm not ready to begin Unity now XD
                  And thanks for one of my best modeling tuto ever.

                  • Siver 2 days, 19 hours ago  | 

                    The tool will work in Unreal engine to. But the last video here is setup in Unity so that part will not work for Unreal Engine.
                    You can follow part 1 , 2 and 3 with Unreal.

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