Rotations: Difference between revisions
Created page with " This article is about rotations in 3D space. ==Representations== The most natural representation of rotations are Quaternions. However rotations can also be represented in v..." |
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Let | Let | ||
\[ | \[ | ||
\mathbf{K} = [\mathbf{k}]_\times | \mathbf{K} = [\mathbf{k}]_\times = | ||
\begin{pmatrix} | \begin{pmatrix} | ||
0 & -k_z & k_y\\ | 0 & -k_z & k_y\\ | ||
| Line 35: | Line 35: | ||
\end{equation} | \end{equation} | ||
\] | \] | ||
==Resources== | ==Resources== | ||
* [https://docs.unity3d.com/ScriptReference/Quaternion.html Unity Quaternion Script Reference] | * [https://docs.unity3d.com/ScriptReference/Quaternion.html Unity Quaternion Script Reference] | ||
Revision as of 17:45, 19 May 2020
This article is about rotations in 3D space.
Representations
The most natural representation of rotations are Quaternions. However rotations can also be represented in various other forms.
Angle Axis
Rotation Vector
Euler Angles
Quaternion
Matrix
Construction=
This section is on converting between different forms of rotations.
How to construct a rotation.
Angle Axis to Matrix
Apply Wikipedia: Rodrigues' rotation formula
Suppose \(\mathbf{k}=(k_x, k_y, k_z)\) is the vector around which you want to rotate.
Let
\[
\mathbf{K} = [\mathbf{k}]_\times =
\begin{pmatrix}
0 & -k_z & k_y\\
k_z & 0 & -k_x\\
-k_y & k_x & 0
\end{pmatrix}
\]
Then our rotation matrix is:
\[
\begin{equation}
\mathbf{R} = \mathbf{I} + (\sin\theta)\mathbf{K} + (1-\cos\theta)\mathbf{K}^2
\end{equation}
\]