Tracking for sky replacment

Hi, I am having problem with tracking a sky. I’ve tried a lot of different shapes, different motion etc, but the track always comes out glitchy/shaking. I will be really glad to give me some advices how can I track it better. The footage is not the easiest to track I think, I am posting the first and the last frame of the clip.


BorisFX released a Mocha Pro tutorial a few years ago about sky replacement using Mocha Pro and Primatte Studio but it involved AE as the host. The tutorial might provide an approach that would be useful to you: https://www.youtube.com/watch?v=a_faH779350

Another BorisFX tutorial about sky replacement from 2 years ago is: https://www.youtube.com/watch?v=7UQcPRNKoiQ

Hope these help.

Already checked those, I forgot to mention that I am using Mocha for tracking and AE for comping, the problem with my footage is that its handheld with a lot of motion and as seen in the screenshots there is a big panning movement in the shot overall. I consider myself semi experienced user with Mocha but I cant nail the perfect track of the BG, I mean it still works but if you are professional you will notice the jitter. Thank you anyway!

Hi Galin,

Sounds like you need to use adjust track to get the camera movement locked down. Have you used adjust track before?

Can you try using adjust track?

Cheers,
Mary

Yes I have definitely have used adjust track, mostly on screen replacements tho, I havent even think about it using it in this situation, because I don’t think I know how to approach it, when I usually use the adjust track with screen I know where the points need to go ( 4 corners of the screen) but in this case I only need the central point(transformation), so I am not sure how can I fix bad track in this shot with adjust track. You can see in the pics that my workflow is to track it and then to apply the transformation that to a null and then attach the new sky to this null. Also for the adjust track should I use the ‘shear’ , ‘prespective’ or only the translation/scale/rotation, because for the track I only used the translation/scale/rotation motion. Thank you.


It looks like you’re tracking multiple planes at once (trees and sky and horizon). What happens if you just track the clouds and use that as the track?

Usually on shots like this I do the very technical “eyeball it and see if it looks right when I adjust it.”

Yes I tried only the sky, kinda works actually, I eyeballed the adjusttrack it as you said and I think it looks decent now, thank you!

As the old VFX adage goes, “If it looks right, it is right.”

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