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Why are quaternions useful?
Quaternions are vital for the control systems that guide aircraft and rockets. Each quaternion has an axis giving its direction and a magnitude giving the size of the rotation. Instead of representing a change of orientation by three separate rotations, quaternions use just one rotation.
How do you multiply quaternions?
Multiplying quaternion numbers
- i*i = j*j = k*k = -1.
- i*j = k,
- j*i = -k.
- j*k = i,
- k*j = -i.
- k*i = j,
- i*k = -j.
Do we really need quaternions in UE4?
But if you use quaternions for handling rotation, you won’t have that problem, because quaternions allow you to handle rotations in a way which is completely agnostic to the directions in which your axis’ point. I think you have one key misunderstanding in your question which is causing all this confusion.
How are quaternions related to the space of rotations?
Unit quaternions represent the group of Euclidean rotations in three dimensions in a very straightforward way. The correspondence between rotations and quaternions can be understood by first visualizing the space of rotations itself. Two rotations by different angles and different axes in the space of rotations.
How to rotate an object in UE4 with 3 controls?
Click and slightly drag every rotation value in object inspector – you should notice that dragging X value rotates object around X axis and so on… Click and slightly drag every rotation value again – this time you should notice that despite having 3 controls for rotation you can rotate the object only around 2 axes.
How does a quaternion work in an editor?
How it works is that the editor keeps current object orientation (as a quaternion) and when you drag-rotate your object it creates a new, relative rotation around selected axis (also as quaternion). Then it concatenates both rotations to compute the result. This way the math works just fine so you won’t see any problems.