Why do interpolated grease pencil strokes deform? I have drawn a 2D Character using grease pencil and I’ve separated the limbs on different layers. When I interpolate the key frames, the strokes will scale or deform in strange ways. I’ve tried adding more key frames but I still have these deformed interpolations. I can go frame by frame and fix the strokes but I'm wondering, can anyone explain why this happens? Or what I can do to prevent this?
First example:
Here the left arm is support to rotate. When I interpolate the frames the arm rotates but shrinks.



Second Example: Here the left arm deforms in shape.
The Interpolate Frames feature is used to transform a stroke from one shape into another, but not really to move a stroke from one place to another whilst maintaining its shape. That's because it draws an imaginary straight line from each of the stroke point's old position to its new position, then makes the point travel along that straight line. For a simple move and/or scale that works, but when rotating a stroke the points should follows an arc, not a straight line, so the shape ends up being squashed by the half way point. You can add a frame at the half-way point, but the problem will happen again on either sides because it's still two straight lines instead of a curve.
For this kind of transformation, instead of interpolating frames you should look into cut-out animation techniques which moves the different parts without changing their shape.