Tracking issue i don't understand

I'm using the planar tracker to track a couple of seconds of a hand. Tracking itself is fine (translation only), everything is green, distance of the movement seems OK. But after i "create planar transform" and use the data to move a small PNG image, it doesn't track properly. It's as if the tracking data got resized smaller and the movements are much more subtle.

Please help me understand the issue and fix it, because i'm starting to lose my mind here...

Your description is correct. Everything is resized compared to the original. The reason this happens is because of Fusion relative coordinates. If something moves from left to right it moves from x=0 to x=1 no matter how many pixels this is. So if you track for example a plane on an HD plate from exactly left to right it will move exactly from x=0 to x=1, which is in actuality 0-1920 pixels. If you apply this to your smaller png that's for example 320 pixels wide. It will still move from 0-1 on the x but this time that's only 320 pixels.

The quick way to fix this is create an empty background for your png to live on that's the same size as your original footage and merge the PNG on top of that, then feed it into your planar transform and it will all be fine.

Wow, thank you soo much, you're a lifesaver. I started to suspect that something is off with the scale, but probably wouldn't have guessed that it's the image size.

It's working now. I could've made a background merge in Fusion, but decided to just make a 1080p image and avoid making the nodes more complicated than they are already.