Real Time Tracking?

Hi, I was just wondering if it was possible to grab a Decklink input into fusion and do real time composition, for example motion tracking? Thanks

No, that isn't possible. Fusion is for post and only works with recorded/filmed/rendered footage.

I saw a custom made plugin which used live input and was then used on set as previz /preview tool
This was many years ago and worked with fusion 5 or so

You're right, under the right circumstances it might be possible.
I was only referring to the default vanilla Fusion versions.

Would you happen to know where I could find this plugin? I can't seem to find it.

you wont find it anywhere, it was a inhouse development of a vfx postproduction and i dont think it was ever develop any further

even if i had a copy of it, if would work with any newer versions of fusion. it was a 32bit app, sdk changed since v5 2x times, ...