Understanding mask and tracking

Hi. I made a video of my screen since this would be a little too hard to explain here.

Basically I want each keyframe to follow the way I add or delete pen points

Try the Magic Mask feature... you may be able to save yourself a lot of time and rotoscoping pain.

If that doesn't work for you then to rotoscope effectively you need to break your object into separate shape parts and move each part separately. You don't want to be creating a single object that constitutes separate parts on either side of pivot points, as that will involve too much movement on each part that needs to be keyframed every frame, rather than simple movements of each part. Think of the target as if it were a puppet. Where are the pivot points? Break it apart accordingly. eg Torso and Head, Upper Arm left, Upper Arm right, Lower Arm left, Lower Arm right, Upper Leg left, Upper Leg right, Lower Leg left, Left Foot, Right Foot.

Personally, if rotoscoping, I'd suggest you do this in the Fusion Page where the tools are more appropriate. Here's a simple tutorial that touches on what you're doing where the tutor is using Fusion to rotoscope a bird and has broken it as an object into two parts (head and body)... head to about 8:50 in the video:

Try the Magic Mask feature... you may be able to save yourself a lot of time and rotoscoping pain.

If that doesn't work for you then to rotoscope effectively you need to break your object into separate shape parts and move each part separately. You don't want to be creating a single object that constitutes separate parts on either side of pivot points, as that will involve too much movement on each part that needs to be keyframed every frame, rather than simple movements of each part. Think of the target as if it were a puppet. Where are the pivot points? Break it apart accordingly. eg Torso and Head, Upper Arm left, Upper Arm right, Lower Arm left, Lower Arm right, Upper Leg left, Upper Leg right, Lower Leg left, Left Foot, Right Foot.

Personally, if rotoscoping, I'd suggest you do this in the Fusion Page where the tools are more appropriate. Here's a simple tutorial that touches on what you're doing where the tutor is using Fusion to rotoscope a bird and has broken it as an object into two parts (head and body)... head to about 8:50 in the video:

Thank you that was a great tutorial actually

Is there a way for me to keyframe the polygon count?
Here's a cenario:
Frame 1 I use the polygong mask tool and draw a square, so four dots. Frame 2 I move that square a little to the side and delete one of the dots on the polygon and now is a triangle.
My issue is: this would apply to frame 1 as well. So because I deleted one dot on frame 2, frame 1 now also has one less polygon dot. But that wasn't my intention. I need for frame 1 to be a square (so four dots) and frame 2 to be a triangle (so three dots).
How do I achieve just that?

You can’t delete or add points when doing roto. Move points together or hide one shape and make another visible if you need this kind of topology changes.

You can’t delete or add points when doing roto. Move points together or hide one shape and make another visible if you need this kind of topology changes.

I now realize