The default studio environment's level-preserving mean of 1 acted like a
100% white Ambient light: with only the Environment light on, a white floor
rendered at full white (95% of the frame saturated) while its shadow core
went to pitch black — a fog over the scene, nothing like After Effects'
default. Three changes bring the look in line, CPU and GPU alike:
- The default environment is a dim studio now: a solid-angle-weighted mean
of 0.3 (and a stronger key gradient), so a white floor reads a mid gray
and the light's colour x intensity still scales the level.
- The shadow occludes only the image's directional (key) fraction of the
light — |sum of dir x radiance| / sum of radiance, computed beside the
dominant direction and carried in the scene — so the fill keeps shining
inside the shadow: an area-light shadow, partial like After Effects'
(a lone bright spot on black still shadows almost fully; a uniform image
not at all).
- The environment shadow map's penumbra has a floor — eight output pixels,
or four map texels where those are coarser — because the map covers the
whole scene bounding sphere rather than the view, and its texels would
otherwise stair-step the edge (all the more in a draft render's flat 512
budget). Shadow Diffusion widens it further, as before.
Tests: the key fraction tracks directionality; the default keeps its dim
level, its direction and its key; the default and a bright key both shadow
the floor (the default partial, the key deep) with Cast Shadows off lit
everywhere; and the full look — a mid-gray lit floor (no fog), a partial
core, and a soft edge ramp in quality and draft renders alike.