The infamous 'At Least 8 Common Tracks' Error in Blender Motion Tracking
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Hello everyone!
In this very short video tutorial, we’ll take a look at one of the reasons why the error "At least 8 common tracks on both keyframes are needed for reconstruction" may appear when trying to reconstruct the motion of a real camera in Blender using Motion Tracking.
The two keyframes Blender is referring to are the ones marked by two yellow lines in the progress bar at the bottom of the Movie Clip Editor. These are usually set automatically by Blender, but you can change them manually by adjusting the values of the Keyframe A and Keyframe B fields in the Solve tab of the editor. It’s generally recommended not to choose two keyframes that are too far apart in the Timeline, so Blender’s default settings work well in most cases.
Looking at the markers, automatically generated in this example using the Detect Features button in the Track tab, it seems there should be no problem tracking at least 8 between the two keyframes, as required by the software. And in fact, that’s true.
However, if we click Solve Camera Motion in the Solve tab, we get the infamous error message, with no further explanation...