The strum plane gets jumpy/unstable when moving the finger at slow speeds.
When the cursor is moving very slowly, it might work to use the plane-to-cursor direction (instead of the cursor motion direction) to calculate the plane normal. This could cause strange effects when moving slowly through the strum plane, since the distances would get very small.
Possibly increase the "smoothing" parameter based on the cursor speed.
The strum plane gets jumpy/unstable when moving the finger at slow speeds.
When the cursor is moving very slowly, it might work to use the plane-to-cursor direction (instead of the cursor motion direction) to calculate the plane normal. This could cause strange effects when moving slowly through the strum plane, since the distances would get very small.
Possibly increase the "smoothing" parameter based on the cursor speed.