Rain fell and the ground did not change: the weather was a curtain of particles in front
of a dry valley.
u_wet, 0 dry to 1 soaked, does the three things a wet surface does. Darkens the albedo.
Drops the roughness hard - which is what makes a soaked meadow read as soaked rather than
merely dark, because the sky glances off it. And pools: water finds the low places and
flat ground holds what a slope sheds, so the puddle mask is the macro noise the materials
already use gated on slope, and a puddle takes the world's up for its normal rather than
the ground's relief.
It joins the shore's existing wet band rather than fighting it - the same term from a
different cause.
34.1% of the frame changes between dry and soaked. GL 7.1 s either way over 400 frames.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>