Two QA sightings from in-yard eye height, both geometry, both reproduced on
dev_skyfx before touching anything. (1) The band stopped AT the camera's
horizontal plane, but the ground's true horizon sits ~0.6 deg below it (the
dip), so a bright sky sliver showed under the base — the floating slab. The
band now overshoots to ~12 deg below the equator; the ground occludes the
overshoot by depth, and it survives scale.y's 0.3 rise floor. (2) The arc-end
fade (sin^0.75) left the outer tenth at ~0.36 alpha — the hard vertical seam.
Now sin^1.6 with the arc widened 2.2->2.6 rad so the solid core keeps its
span while the ends drop under 0.12.
Verified by eye on dev_skyfx (southerly t=24, front 0.51): base meets the
ground line, no sliver, no seam. Selftest 338/0/0 (+1 test pinning both in
numbers). Mutation-checked: the old thetaLength and the old exponent each red.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
c2a19df7d5