The detail that caught me off guard: a closed loop of cyan points drawn along the seam between sleeve and torso, one tap on Start cut, and the left arm comes away as an independent part, hauled aside with gizmos. No manual mesh surgery, no boolean cleanup, just a hand-drawn curve.
The feature is Curve Split, built into AIMIA's 3D Editor in MakerLab. The workflow runs in three steps: draw the region, tweak the cut surface, then execute. For the adjust stage there is a choice between Planar fill and Bulge fill, and the maker goes with Bulge fill before pulling the Area slider from 51.3% down to 18.2%. Height sits at 4.2 mm, taper angle at 10 degrees, tolerance at 0.2 mm. A direction gizmo sits on the green highlighted joint surface to steer the cut, and after starting, a Saving dialog appears briefly.
The demo model is a cartoon boy figurine, and the cutter menu lists more than one option, with Hinge Cutter and Shell Cutter alongside. The color parameter is set to PLA Basic Silver. Alignment pins can be dropped in straight away for easy assembly. That strikes me as a natural companion to a curved seam like this one.
One thing still open: whether the tool ends up as part of MakerLab, a plugin, or a standalone package has not been confirmed. The AIMIA beta is being rolled out in waves through MakerLab.