What's real here?
Real: the arm's motion. Every move was planned ahead of time by the
DimOS motion planner for a simulated xArm7, with the
scanned head and neck and the shoulders as obstacles. This page replays those plans.
Modelled on the real mechanics: the gripper's fingers sit in the scissor rings, so the
gripper closing is what closes the blades, at the speed the arm model allows. The arm only moves sideways above
the hair, because scissors dragged through hair would snag it. For each snip it goes straight down, lifts the hair on
the comb, stops, and closes the blades.
Simulated in your browser, as it happens: every strand the tool or other hair touches. It keeps
its length and curl, bends under gravity by real hair's stiffness, and can't pass through the scalp or the tool.
Hair is crowded out of full spaces and drags on nearby hair. Move a tool sideways through it and strands catch on the
tines, go taut, slide along, or snap at hair's breaking force, and fast-moving hair can knot. Those pull on the arm, and past a
limit it holds still. Cutting pushes back on the gripper, and clippings land on the cape, chair, floor or in the hair.
Estimates: the cutting force per hair, the scissors' weight, the arm's pull limit, and how readily
hair catches and knots. Torques are holding torques, from the arm model's masses.
Left out: strands interact through a grid, not one by one, so they can still pass through each other
and through the thinnest tool parts. The arm follows its planned path exactly, with no bending or control lag. There's no
real robot or client, and the scissors and comb are a design that hasn't been built.
The DimOS planner isn't running live, so buttons play moves already planned. "Drive it yourself" uses a simple
solver in this page, which only keeps the tool off the scalp and doesn't check the rest of the arm.
On screen, the yellow dots are hair resting on the comb. The Overlays button hides them.
xArm model licence
Head: "Infinite, 3D Head Scan" by Lee Perry-Smith, CC BY 3.0, based on a work at triplegangers.com, via three.js; hair and scalp shading added (notice).