Hello,

I was trying to study how the tangents are decided/calculated from the TCB values. So I came across this file and saw how the in-tangent and out-tangent are calculated. It uses bezier between two waypoints.

Now I created a star layer and three waypoints and tried to predict there motion using the in-tangents and out-tangents but got some unexpected results.

The file I am using is MovingStar.sifz (861 Bytes)

All the waypoints used have TCB interpolation methods(both in and out).

I will show the calculation of in-tangent at waypoint 2:

I am assuming that all the tangents are calculated with respect to the waypoints. That is the in-tangent is calculated with respect to waypoint-2. Please correct me if I got this wrong.

Now in the above image, â€ś`T`

â€ť represents what I expected to be the tangent should have been. But when you open the attached file in synfig and run it, you will get the tangent â€ś`O`

â€ť approximately(I donâ€™t know how to find the exact co-ordinates).

Please tell me where am I going wrong or did I miss something?