Hasta La Motion!

i am currently trying to learn PFTrack, i started with motion capture, which i got it to work smoothly. what i’m having trouble with at the moment is camera tracking, i have the test objects sticking, which is good i guess, but then i could never get the grid to stick to the actual ground plane in the footage.

i used to think tracking a shot will require measurements of camera aperture and focal length, then i watched some dude track a shot with PFTrack on Youtube without the measurements, so i went and tried myself, but it’s not working.

can some one give me a definitive answer? do i have to have the exact measurement of camera aperture and focal length to track a shot?

thanks for you time.

Ding