Faking Depth of Field in Fusion

Ok, I'm relatively new to Resolve, but I just spent a while trying to find this answer, and now I'm here.

I'm editing video footage for a short film (In the free version of Resolve). I'd like to try and fake some depth of field. I've done the node thing in the color corrector, outlining the background and such, tweaking it frame by frame, and then blurring, but it takes a LONG time.

I was hoping there was a way to use the Planar Tracker in fusion to track my subject, and then invert that in order to blur the background. This sounds like it should be easy, but I'm at a loss.

Any suggestions?

I appreciate your help!

Difficult to advise on this without further explanations or images. But do you know that Fusion offers a full 3D environment, not 2.5D like AE?
There are free tutorials by BM for Fusion.

For fake dof doing a roto and a depth blur is basically the way. What you can try is magic mask in color page, it might ease the workload if produced quality is good enough for you.

You can use planar tracker to make roto work easier, but it is still a tedious job. Main thing to keep in mind with planar tracking (in every software) is that track solve is based on assumption that surface you track is planar (or reasonably flat) and its movement can be described with perspective transform. So it can't properly track arbitrarily deforming surfaces, you must break shapes up into pieces that don't deform much and track/animate them separately.