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Unity Editor default install location:

This is my exploration of a workflow from an HDA in Houdini to Unity and augmented reality through Houdini Engine for testing HDA controls and visualizing updates. Augmented reality filmed with an iPad Pro and video/sound editing processed in After Effects.

The intent is to understand the accessibility of HDA parameters in Houdini Engine for user manipulation during runtime of Unity, and particularly through augmented reality. I envision this process as a way of testing HDA's before baking them into assets and scripting potential interactivity actual deployment to an independent augmented reality application.

Versions used in test:

The first bit is a quick overview of the test followed by a narrated breakdown of the workflow. This is primarily documentation of my academic research and not intended to be a tutorial, but the workflow does detail applicable HDA scripts and libraries.

Initial HDA setup in Houdini with exposed parameter controls.

Houdini Engine control panel in Unity with parameters accessed via C# script.

UI elements and scripts in AR. The asset rotation is managed with user touch controls on the mobile device and world space UI, while the material color variation is defined through a color picker on on the screen space UI.

Exploration of workflow from generating a pyro sim and texture sheet composition in Houdini to a Unity particle system for use in augmented reality. My aim is to explore how sims from Houdini might be able to capitalize on these workflows and evaluate its performance in AR compared to other simulation solutions. Augmented reality filmed with an iPad Pro and video/sound editing processed in After Effects.

Exploration of workflow from generating visual effects in Houdini to Unity for use in augmented reality. The intent is to identify optimal strategies for showcasing complex effects in augmented reality. For instance, Houdini's game development toolset includes a ROP for generating texture sheets by rendering the effect and then compositing layers within a base and normal texture, or Houdini's Vertex Animation Texture (VAT) Rendering Operator outputting to Unity's Universal Rendering Pipeline (URP). My aim is to explore how sims from Houdini might be able to capitalize on these workflows and evaluate its performance in AR compared to other simulation solutions. Augmented reality filmed with an iPad Pro and video/sound editing processed in After Effects.

Houdini's Vertex Animation Texture (VAT) Rendering Operator outputting to Unity's Universal Rendering Pipeline (URP) for visualizing in augmented reality. The intent was to understand the workflow within Houdini and implementing its output in Unity's URP.

Test for coordinating multiple targets and linking their corresponding game objects with cast ray and attraction forces with Unity's Visual Effects Graph.

This short video documentation depicts my exploration of using the HTC Vive Tracker with the Vive system to enhance indoor rowing with a custom, interactive virtual environment. The Vive Tracker is attached to the handle of the Concept2 Indoor Rower and linked with scripts in Unity to the virtual oars for propelling the boat in the virtual environment.

As an example of a great application that can be enhanced by the Vive Tracker, I am developing a virtual rower that attaches the HTC Vive Tracker to the handle of a Concept2 Indoor Rower. It uses the HTC Vive headset in conjunction with the custom virtual environment created in Unity Pro. Check out the video documentation to see it in action:

Pairing the Vive Tracker

Tracked Object Assignment

Vive Tracker 3D Model

Source: https://www.vive.com/us/vive-tracker-for-developer/

This asset was downloaded and integrated into the Unity scene as a placeholder and reference for positioning and orientation. In the Virtual Rower, I set it to be transparent so that it was still visible for reference, but not intrusive to the virtual environment. With the representation of the Vive Tracker 3D model in the Unity scene, it was attributed with the script Steam VR Tracked Object so that the Steam VR Controller Manager could identify is as a tracked object.

Enable post-processing via Package Manager and deploy to AR using URP.

AR Foundation

XR Plugin Management

ARKit XR Plugin

XR Interaction Toolkit

Workflow - Vuforia Developer Portal

Workflow - Unity

The other challenge emerged during the build process from Unity. The builds were processed using the Unity Cloud Build service by linking the Unity project files through a BitBucket repository that was, in turn, linked to the Unity Cloud Build platform. The following lines from the first attempt’s Unity Cloud Build log file noted the issue that needed to be resolved before the build could be completed. The Vuforia package within the Unity project has .dll files located in its plugins folder.

Verify Vuforia updated to latest release via Package Manager.

Buildtime Issues

Unity-iPhone

Unity-iPhone

Runtime Issues

The following is my documentation of following the tutorial guide noted in the source link above, along with additional notes from my experience in working in this setup.

From the Package Manager, access Show preview packages and install the following, which are specific to ECS.

By default, the Unity project is initiated with 4.x, but the following warning notes that it should be set to 2.0 for ECS DOTS to run correctly. Based on my initial tests attempting to run some operations with entities, Unity locked up in game mode under 4.x, but then ran correctly without issue as soon as the project was set to 2.0. Though this does not confirm that the .NET Standard setting is the direct cause of the lockup, it did appear to resolve it.

To make the change to .NET Standard in the Project Settings, navigate to the Player section and use the drop-down menu next to API Compatibility Level, as shown below.

While the traditional Monobehaviour allows for mixing data, actions and methods, ECS is compartmentalized as such:

Organization

In runtime, the Entity Debugger shows the entities currently deployed to the scene. Note that WorldTime is a default entity that stores the world time data. It is created automatically by Unity. The other entity currently shown is empty and simply a 'thing' awaiting to reference 'data'. The entity is just an identifier with a id, while the data is held somewhere else. The entity will simply reference the data rather than actually hold it.

Traditional game objects have data already assigned to them like Transform and others, but ECS requires that each of these datum be created and referenced individually. This compartmentalization is where the efficiencies lie in ECS over the traditional game object method, particularly as many entities and data are added to the scene.

An entity created using a defined archetype shows additional data per the archetype. In this case, the archetype included data of Transform, Rotation, RenderMesh, RenderBounds, LocalToWorld, and Unity created a few other automatically.

Once an entity has acquired a format with an archetype, data can be applied and linked for use by the entity. Methods include the following:

These experimental drops are not a Package Manager supported package, so they will not show up in the Package Manager even with Show Preview Packages enabled. Regardless, the drops can be downloaded and installed to the recommended Unity version for testing. As of drop 10, the relevant line is provided for adding to the project manifest.json file, located in the Packages folder.

A quick way to get the latest version is to go the to forum and search for the following DOTS Visual Scripting Experimental Drop with Search titles only enabled and Data Oriented Technology Stack selected in the Search in Forums field. This will output only those threads relevant to the DOTS Visual Scripting and the latest drop.

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