Inside the wall every instance is a mesh whose LOD2 casts its shadow, so a card is neither drawn nor
cast there: fog_impostors.ludic frees a layer's atlases while wall + margin < its near (trees 420-480
m, rocks 320 m) and paints them again from the model when it opens past it (impostor_paint, split out
of the bake). Impostor atlases get memory of their own, so a release goes back to the driver instead
of leaving a hole in a shared block. R3D_FOG_AT=<frame> with R3D_FOG_TO=<m> changes the wall mid-run.
At the overlook: 2102 MB off, 1824 MB at 30 m (249 -> 67 MB of atlases; the rest is the ground cover's
card atlases, drawn inside the wall); opening re-bakes 16 layers in 42-46 ms, back to 2102 MB.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
