i'm using Unity 3D engine for a certain project. In the project I need to create animation curves on-the-fly.
In Unity, animation curves are represented as keyframes containing (Time, Value, InTangent, OutTangent). Each component of each possible transformation is represented a single curve (for example, rotation is represented using 4 curves, one for each of the four quaternion components (x, y, z, w)). So, in total there are 10 curves(3 position(Vector3), 3 scale(Vector3), 4 rotation(Quaternion))
For example, if i wanted to create animation that moves an object on the x axis by 5 units in 1 time unit I would add a curve for "Position.x" with two keyframes (0, 0, 0, 0), and (1, 5, 0, 0). As you can see, InTangent and OutTangent are set to zero, as I simply want linear interpolation between the two keyframes.
However, when doing rotation, InTangent and OutTangent need to be set to some value, and I don't know how to calculate that value. What I want to know, is what could InTangent and OutTangent variables be, and how to calculate them? All I know, is that they are at 0 when I want linear interpolation.
Unity describes InTangent and OutTangent as:
InTangent - Describes the tangent when approaching this point from the previous point in the curve.
OutTangent - Describes the tangent when leaving this point towards the next point in the curve.
But I don't know how to calculate those tangents when I want rotation.
EDIT:
Just to make it easier to visualize:
I have curve on the left, and I want to get the curve on the right. And I get that curve by properly setting the InTangent and OutTangent values at each of the keyframes. (This is done using Unitys animation editor, that does this automatically).
