Hi Tudor,

re:
> 1. after saving with annotations, reloading annotations will change positions !

There is a bug with the anchor point switching around when you save/reload annotation text block objects, it's fixed for the next beta.


> 2. crv - evaluateCurvature - understand it's trying to evaluate several connected control pts ?!?!?!

I'm not sure what you're asking here.


> 3. tg - evaluateTangent - shoudn't be perpedicular ?

No, a curve tangent is not perpendicular to a curve, it's the direction the curve is traveling in at that point, like this:



> 4. evaluateDerivatives - what are those ? (1,2,3 - too far away, pointed direction)

That would take a long time to explain, you could try some online descriptions like:
https://demonstrations.wolfram.com/TheDerivativeVectorsOfABSpline/

Or check out:
"NURB Curves: A Guide for the Uninitiated" by Philip J. Schneider
https://vintageapple.org/develop/pdf/develop-25_9603_March_1996.pdf

These values are vectors that represent directions, it maybe sounds like you're interpreting them as point location values instead of vector directions?

- Michael