Mon Mar 18, 2024 8:05 am
Just out of curiosity, why would you export planer tracking data to Blender, instead of compositing with such tracking data in Fusion a proper compositor. If you are dealing with 3D space you have the data in your 3D scene, and if you need to composite CGI footage with live action video footage, it makes a lot more sense to do it in Fusion, does it not?
Also I am not sure if you can export tracking data natively from Fusion, maybe with some script or something, but I know Fusion does not save a lot of tracking data upon finishing the track and when you close the composition.
What the Planar Tracker Saves
While the Planar Tracker does save the resulting final track in the composition on disk, it does not save temporary tracking information such as the individual point trackers (compared with the Camera Tracker, which does save the individual point trackers). Some consequences of this include:
— The point trackers no longer appear in the viewer when a comp containing a Planar Tracker node is saved and reloaded.
— Tracking may not be resumed after a comp containing a Planar Tracker node has been saved and reloaded. In particular, this also applies to auto saves. For this reason, it is good to complete all planar tracking within one session.
— The size of composition files is kept reasonable (in some situations, a Planar Tracker can produce hundreds of megabytes of temporary tracking data).
Planar Transform Node [PXF]
The Planar Transform node applies perspective distortions generated by a Planar Tracker node onto any input mask or masked image. The Planar Transform node can be used to reduce the amount of time spent on rotoscoping objects. The workflow here centers around the notion that the Planar Tracker node can be used to track objects that are only roughly planar. After an object is tracked, a Planar Transform node can then be used to warp a rotospline, making it approximately follow the object over time. Fine-level cleanup work on the rotospline then must be done.
Depending on how well the Planar Tracker followed the object, this can result in substantial time savings in the amount of tedious rotoscoping. The key to using this technique is recognizing situations where the Planar Tracker performs well on an object that needs to be rotoscoped.
A rough outline of the workflow involved is:
1 Track: Using a Planar Tracker node, select a pattern that represents the object to be rotoscoped. Track the shot (see the tracking workflow in the Track section for the Planar Tracker node).
2 Create a Planar Transform node: Press the Create Planar Transform button on the Planar Tracker node to do this. The newly created Planar Transform node can be freely cut and pasted into another composition as desired.
3 Rotoscope the object: Move to any frame that was tracked by the Planar Tracker. When unsure if a frame was tracked, look in the Spline Editor for a tracking keyframe on the Planar Transform node. Connect a Polygon node into the Planar Transform node. While viewing the Planar Transform node, rotoscope the object.
4 Refine: Scrub the timeline to see how well the polygon follows the object. Adjust the polyline on frames where it is off. It is possible to add new points to further refine the polygon.
Nodes in Fusion can be saved out and imported as plain text, not sure if there is a way to use it in Blender, or some plug in for it in blender. But in terms of workflow it seems more sensible to composite in fusion not in blender.
— Saving and loading of compositions is faster and more interactive.
