Methodology for tracking closeup of a computer screen with only one edge visible

I have just finished watching the amazing tutorial by Mary Poplin May on Adjusting tracks that go offscreen: Office Hours 17: Adjust Tracks that go Offscreen! [Boris FX Learn With Mary Poplin May 10th 2022] - YouTube

My issue is that I need help with a screen replacement for a rendered video (3D environment coming from blender). The video starts on the bottom right corner of the screen and then the camera moves up until it hits the top right corner of the screen. Tracking either corner is easy enough as I have the frame of the computer. However in the middle I only have the right hand edge displayed and because of the minimal detail (in the full rendered frame, not just the computer bezel), there is not enough to track the vertical movement in this region - I understand I will need to do this manually.

I do not know how to achieve this though. I have about 30 frames where I need the surface to smoothly move in the vertical plane only. I have been trying for about three days to get something usable and I cannot progress. Any guidance would be appreciated.

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Unfortunately, if there’s no visible details at all - there’s no data for Mocha to track. You either need to switch to Manual Track or AdjustTrack module. That stream was great and it covers great techniques. But I want to share one more video with you, where the object gets completely out of view. Maybe this one will be more helpful in your case. Quick Tip: Manual Track - YouTube

But looking on this case from the 3D side - did you mean that only your insert is created in Blender, or the whole scene is 3D? If the latter, then there are a few more suggestions:

  • You can render UV Pass out of Blender. UV Passes are used for re-texturing 3D objects in a compositing software’s like Nuke or AE. But they also can be used as a “placeholder” for the inserts.

  • Or, just change your object’s material/texture to some sort of grid, and render that out. Now, try this second version for tracking only, and use that track data to comp your insert over the original one. Profit! I think this would be the fastest and the easiest workaround, if you have access to re-rendering that from Blender.

Hope that does make sense to you! Let me know how it goes

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I feel like such an idiot - I guess that’s all part of the learning process. This is an easy way to give mocha something to track. The best part is there is no manual correction to be had since there is a lot of detail. The screen replacement really is as quick as creating a couple of splines each time one goes out of frame. Perfect. Thank you

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Glad to help! :wink: