Measured in the source geometry (Art/blender/site/site-2026-11-06.blend, metres): at the player's street section the north sidewalk tops out at 1.58 m and the road at 1.45 m. The 380 cm that has driven every placement decision came from the UE mesh's bounding box, which spans 279 m of sloping street and takes the highest point anywhere - 2.2 m above the surface where the player stands. That is the float, quantified at last. Moving the invisible collision slab to a 158 cm top did not work: with an 8 cm slab the player fell to Z -4410, and with a 50 cm slab it fell to the same place, so the slab was not colliding at all after the change. I could not identify why within this pass, so the change is reverted and the 380 stopgap restored - verified again by trace (mesh=Cube at Z 380, actor Z 470). Recorded in TODO.md with the two numbers and the next step: find why the slab stops colliding when it moves down, then set it to 158 and the player start to 247.
772 KiBLFS
772 KiBLFS