IPO curve keys interpretation and manupulation

Hi everyone!

With a reference to this thread http://blenderartists.org/forum/showthread.php?t=150170, currently I have some problems with keys (nodes) of IPO curves as I am trying to manipulate IPO curves by a Python script.

Basically, what may be the interpretation of values of IPO curves? When I read an IPO curve key (node), I get a BezTripple which gives me the left handle, point and the right handle of bezier point. As per the point, there are three floats - time (frame), value and ZERO(?!) The value corresponds some how to the location, rotation, etc. of the object (bone). I know this but I dont know HOW… and WHAT is the relation. I am particularly interested in values for rotation (QuatX,QuatY,QuatZ). I dont know what QuatW stands for though… But if I rotate a bone 30 degrees on X, the value in IPO curve is 0.258819043636. So I am interested in the reverse task - to calculate the corresponding rotation angle of a given IPO curve value. Do you know how many degrees correspond to IPO curve value of 0.113203212619? :eek: