Скачать или смотреть Mastering Quaternion Rotation Inversion in Unity

Learn how to effectively invert rotation around a certain axis using quaternions in Unity game development with easy-to-follow steps.
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This video is based on the question https://stackoverflow.com/q/74142047/ asked by the user 'THG' ( https://stackoverflow.com/u/15032514/ ) and on the answer https://stackoverflow.com/a/74192505/ provided by the user 'THG' ( https://stackoverflow.com/u/15032514/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Mastering Quaternion Rotation Inversion in Unity: A Simple Guide

In game development using Unity, working with rotations can often be daunting, particularly when it comes to using quaternions. For many, understanding how to manipulate rotations may take some time, especially when you need to invert certain components of a quaternion. In this guide, we’ll explore a common issue faced by many developers: inverting rotation around a specific axis using quaternions, and I’ll provide a simple yet effective solution to achieve the desired results.

The Problem

Imagine you have a quaternion-based rotation in Unity represented by the variable pose. You may want to modify this quaternion to reflect a change in rotation that results in different Euler angles. Specifically, you have a quaternion that results in Euler angles (1, 2, 3), but you want to modify it to achieve the rotation (-1, 2, 3).

With this challenge in mind, you might try methods like this:

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

You may find that this approach does not yield the correct results, leaving you puzzled and in search of a more efficient method.

The Solution

After experimenting and troubleshooting this issue, I discovered a more effective approach. The trick involves storing the inverted rotation in a Vector3 variable before applying it to the target game object. Let's break down the steps to implement this solution:

Step 1: Assign Initial Rotation

Start by setting the rotation of your initial game object using the pose.rot quaternion. This step ensures that the object has the correct initial orientation.

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

Step 2: Create a Vector3 for Modified Rotation

Next, create a new Vector3 that will hold the modified Euler angles. In this case, only the x-axis value is inverted, while the y and z-axis remain unchanged.

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

Step 3: Assign Modified Rotation

Finally, set the rotation of the second game object using the modified Vector3 you just created. This approach applies your changes correctly and with the expected outcome.

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

Complete Code Example

Putting it all together, your code would look like this:

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

Conclusion

Working with quaternions and rotations in Unity can be complex, but understanding how to manipulate them makes a significant difference. By following the steps outlined above, you can effectively invert rotation around a specified axis to achieve the desired Euler angles. This solution not only resolves the immediate problem but can also serve as a reference for future quaternion manipulations in your game development endeavors.

Should you run into similar challenges, keep this guide in mind. Inverting rotation can lead to impressive results when done correctly! If you have additional questions or further issues, feel free to reach out or leave a comment below. Happy coding!