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February 2020

Oculus Quest Development with Houdini Unity and USD

Oculus Quest Development with Houdini, Unity and USD

Part One

This is the first in a series of articles where I look at Oculus Quest Development with Houdini, Unity, and USD. USD is Pixar’s comprehensive scene format, Universal Scene Description. I first saw the power of USD a few years ago during a Pixar demonstration that showed its power. For example, it was able to render scenes with 20+ million polygons in real-time. Now that Houdini 18 has Solaris, which is built on USD, it is now possible to easily read and write USD files.

Oculus Quest Development with Unity

First, let’s look at the Oculus Integration package in Unity. We want to make sure that we have the correct settings. In my examples, I am working in Unity 2019.3.f6. First, I always switch the platform to Android when creating a new project for the Quest. Next, I set the texture compression to ASTC. This can take time depending on how many textures there are in the project.

Oculus Quest Player Settings in Unity


Next, we want to make sure the player settings are correct. With the player settings open we want to make sure of the following:

  • Remove the Vulkan API from the Graphic APIs
  • Color Space is set to Linear
  • That you have the Oculus SDK installed in the XR settings.

Stereo Rendering Mode – I have Single Pass selected. I have this based on that Multi-Pass has been broken so far. Oculus released a new version February 6th but I have not yet tested Multi-View

Installing USD in Unity

Installing Universal scene description is easy. First, go to window / package manager. This will open Unity’s Package Manager. Under Advanced, we need to make sure that show preview packages are checked. Lastly, now that we have preview packages selected, all we have to do is install USD. Find USD in the list and click install.

Lastly, if you don’t want to use the Package Manager you can always pull from Unity’s USD Git Hub

Once USD has been installed, a new USD menu will appear. This is where we can import and export USD files.  Unity gives us the option to import a USD as a game object, a prefab,or a timeline clip. Furthemore, Unity gives us the option to export USDZ,the zipped format for USD.

USD in Houdini with Solaris

Other Houdini Tutorials:

Point Transformations  in Houdini

Point Transformations  in Houdini

In this introductory tutorial, we look at point based transformations in Houdini. As well, we will look at attribute-based point transformations. For example, attributes can be color, normals, velocity, or anything else. Point transformations are fundamental for many effects created in Houdini. Above all, position in Houdini is just an attribute. As a result, we can manipulate it like any other attribute. Using a VOPs based approach we will look at the Mix VOP. For example, the Mix VOP will allow us to mix two vectors, and then blend between them. Moreover, Houdini has the unique ability to operate on the point level. As well, Houdini has the ability to embed any attribute on points. Therefore, we can blend anything from position, color, and normals. In truth, we can blend whatever we like. Lastly, we will look at how we can use this with a copy to points and metaballs. We will look at how we can adjust the display settings to view the metaballs correctly. In Conclusion, the user should have a solid understanding of:

  • Using Scatter to keep consistent point counts.
  • Basic VOPs Skills.
  • Blending Attributes.
  • Using the Copy to Points.
  • Using Metaballs in Houdini.
  • A better understanding of vectors in Houdini.

This tutorial will provide a basic understanding of VOPS in Houdini. For Example, VOPS allows us to visually place nodes in place of Code. VOPS stands for Vex Operators. Vex is Houdini’s internal language for creating and manipulating geometry.

You can download a free version of Houdinihere

Other Houdini Tutorials: