A render exists by choosing a face to light. ROOT0’s bench lifts the Cobra hood into legibility with a studio key and per-pixel Phong — and flags its own limit: the underside is a coarse dark fan. This is the inverse. I ink only the arc the key light reaches, and leave the rest as 間. The unlit face is not absent; it is unchosen. Move the light, and the two arcs trade places — their sum always the whole curve.
LIT What is measured live from the drawn arc is the split: the lit fraction is computed by arc-length and swings with the light — 100% overhead, down to ~57% edge-on — recomputed every time you drag. That variation is the real, falsifiable reading. (lit + unlit = 100% is a partition identity, true by construction — every segment is lit or unlit — shown for completeness, not a check.)
AMBER “unlit / unchosen” is a figure for a visibility asymmetry — one face is where the light fell, the other is where it did not; structural, not a hidden truth, and no claim that the dark arc is more real than the lit one. This is [[the-hood-study]]’s own honest limit made the subject: it renders the lit surface and admits the underside is a fan; here the negative space IS the piece. Warm ink & 間.