Скачать или смотреть Resolving the Matrix4x4 Not Found Error in Unity for HoloLens 2 Projects

Learn how to fix the `Matrix4x4` not found error in Unity for HoloLens 2 by adjusting the .NET version. This guide guides you through the necessary steps to ensure your project runs smoothly.
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This video is based on the question https://stackoverflow.com/q/68459428/ asked by the user 'Ignacio Alorre' ( https://stackoverflow.com/u/1773841/ ) and on the answer https://stackoverflow.com/a/68459659/ provided by the user 'Ignacio Alorre' ( https://stackoverflow.com/u/1773841/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Troubleshooting the Matrix4x4 Issue in Unity for HoloLens 2

If you're developing a project in Unity for HoloLens 2 and you encounter the error message claiming that the reference to type Matrix4x4 is defined in System.Numerics, but it cannot be found, you're not alone. This issue has baffled many developers, particularly those who have imported older projects or libraries. Let's break down how to diagnose and resolve this problem step-by-step.

The Problem Explained

You may see error messages in your console similar to this:

[[See Video to Reveal this Text or Code Snippet]]

Additionally, you might notice that other crucial classes like Vector3 and Vector2 are also missing.
Such errors often stem from compatibility issues between your Unity setup and the .NET version referenced in the project. Here’s what you can do to address it.

Solution Steps

The crux of the solution is to ensure you are using the correct version of .NET for your project. Follow these simple steps to change your project settings in Unity:

Step 1: Open Build Settings

Launch your Unity Editor and open the project experiencing the error.

Go to the File menu at the top left and select Build Settings.

Step 2: Access Player Settings

In the Build Settings window, you will see a button labeled Player Settings. Click on this button.

Step 3: Navigate to Other Settings

Once you are in Player Settings, find the Other Settings tab. This tab contains various configuration options for your project.

Step 4: Change API Compatibility Level

Look for the Api Compatibility Level option. This is crucial for resolving the Matrix4x4 issue.

Change the .NET version from the default (which is typically set to a lower version) to .NET 4.x. This adjustment allows access to the newer features of the System.Numerics library, including the Matrix4x4 structure.

Step 5: Save and Rebuild

After making the adjustment, be sure to save your changes.

Finally, try rebuilding your project. This action should resolve the missing references, and the error messages should disappear.

Conclusion

Dealing with compatibility issues in Unity, especially in cross-platform development for devices like HoloLens 2, can be challenging. However, by ensuring your project is using the correct version of .NET, you can prevent or resolve many of these issues, including the Matrix4x4 reference problem. If you continue to face difficulties, consider checking other plugin or library dependencies that may also require updates to work seamlessly with your Unity version.

By following these steps, you can get back to developing your exciting project for HoloLens 2 efficiently!