Orientation and Marker weights

[Arthur Kipel]

Hello!
We build a motion-capture system based on IMUs (which provide orientation) and trackers (which provide orientation and position). So we use IKSolver with orientations and markers. But sometimes trackers can have invalid state, in this situation we need dynamically turn off orientations and markers from such trackers. We thought that it can be done setting corresponding Orientation and Marker weights to 0. But in this case skeletal model sometimes turns to corrupted blocked state.
So we want to know how dynamically turn on/off markers and orientations in Inverse Kinematics. And also we would like to have more info about mechanism of orientation and marker weights, how they work.
Thanks.