Just a quick note on the matchmove tutorials - you shouldn’t use the ‘greenscreen’ thing you’re showing. When you’re going from CG into any compositing program you want to use alpha channels or masks, not mess around with chroma keying. You also run the risk of antialiasing the edge of the CG object against the green background and having to remove the AA ‘spill’ later, when it should be done against a black background or even the original background.
You could just create a rectangle a similar color to whatever the sphere’s sitting on (to get some GI spill on the sphere) and comp the video using the shadow pass set to multiply, on top of that the sphere footage using the sphere object mask as an alpha channel.
The track came out good, though… I’ve been pretty impressed with Matchmover since I got it.