Construct Virtual Marker in a local coordinate system

Hello everybody,

I have made a recording of the pelvic with Vicon. There are 6 markers placed on the pelvic. The problem is, sometimes two of the markers ar missing for a whole trial. Now my idea was to build a local coordinate system (what I have allready done), with the orthogonal vectors, v1, v2, v3.

Now I want to get the possition from the missing marker (p1 and p2) from the calibration file, and describe it in the LCS (v1,v2,v3).

Can I now just take the vector pointing to the missing marker? p1 - origin of the LCS And how can i implemet this point to my file with 230 frames?

Thanks for your help! Oliver