Скачать или смотреть Transforming 3-component Android Rotation Vector into 4-component Quaternion for Unity Applications

Learn how to convert 3-component Android Rotation Vectors into 4-component quaternions for seamless rotation in 3D applications like Unity.
---
This video is based on the question https://stackoverflow.com/q/62697790/ asked by the user 'tristndev' ( https://stackoverflow.com/u/5604353/ ) and on the answer https://stackoverflow.com/a/62697791/ provided by the user 'tristndev' ( https://stackoverflow.com/u/5604353/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Transform 3-component Android Rotation Vector to (4-component) quaternion

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Transforming 3-component Android Rotation Vector into 4-component Quaternion for Unity Applications

If you're diving into the world of mobile applications and 3D game development, you might find yourself needing to work with sensor data to create immersive experiences. One such task is converting the 3-component Android Rotation Vector from your smartphone into a 4-component quaternion that can be easily utilized in 3D environments like Unity. This guide will walk you through the steps involved in achieving this transformation. Let’s get started!

Understanding the Android Rotation Vector

The Android Rotation Vector constitutes a representation of the device’s orientation based on the three rotational axes — roll, pitch, and yaw. This vector forms the basis for understanding how your smartphone is tilted and turned in space.

However, while working with 3D applications, especially in Unity, a quaternion representation is often preferred due to its efficiency in handling 3D rotations. This is where the conversion comes into play.

What is a Quaternion?

A quaternion is a mathematical construct that can be used to represent rotations in 3D space without suffering from gimbal lock—a common issue when using Euler angles. A quaternion is generally represented as a 4-component vector <q0, q1, q2, q3>, where:

q0 is the scalar part.

q1, q2, q3 are the vector parts.

Why is Conversion Necessary?

The reasons to convert from a 3-component rotation vector to a quaternion for Unity include:

Smooth Rotation Handling: Quaternions allow for smooth interpolations and rotations between states.

Avoid Gimbal Lock: They provide a more stable representation of rotational elements.

Easier Storage: Quaternions can encode rotation information more compactly than Euler angles can.

The Conversion Process

Step 1: Understanding the Quaternion Components

The first step in transforming the 3-component rotation vector to a quaternion is understanding how to express the components of the quaternion. According to the industry standards for unit quaternions and the relationship between rotation vectors, you can consider the last three components of the quaternion to be equivalent to the three components of the rotation vector.

Let us assume the rotation vector is represented as:

x, y, z

Now, the quaternion can be expressed as:

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

Step 2: Calculate the First Component q0

Since the quaternion must remain a unit quaternion, we can deduce the first component q0 from the remaining three components. Using the unit quaternion property, we have:

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

This implies:

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

This equation allows us to efficiently calculate the scalar part of the quaternion based on the vector components derived from the rotation vector.

Step 3: Putting It All Together

Now, armed with the knowledge of how to derive q0, along with the values of q1, q2, and q3 directly from the rotation vector, you can formulate the complete quaternion for use in Unity.

Summary of Steps

Extract the 3-axis components (x, y, z) from the Android Rotation Vector.

Compute q1, q2, and q3 based on those components with the intent of representing rotations.

Calculate q0 using the formula derived to maintain the quaternion's properties.

Conclusion

Converting a 3-component Android Rotation Vector to a 4-component quaternion involves understanding the mathematics behind quaternions and the relationships between rotation vectors and quaternions. By following the steps outlined in this guide, you can smoothly integrate smartphone sensor data into your exciting Unity projects, leading to more i