CityGen 0.4.1 (Windows)

CityGen 0.4.1 Release Notes

Released on August 20, 2026.

This is a patch release for the extracted-asset ground offset refactor. Building
placement already read the authored ground_offset; this release extends that
same offset path to roads and fill props so every marker-authored asset seats
from extracted metadata instead of assuming a hard-coded flush origin.

Highlights

• Roads and trees now seat from extracted asset metadata. The city
  constructor no longer treats them as implicitly flush assets with a baked-in
  0 Y offset.
• Road/fill schematics now persist their authored ground offset. The
  extraction stage writes the asset ground seat into the Sponge Offset field,
  and the loader preserves it through rotation and composition.

What Changed

Unified offset plumbing

• pipeline/01_roads_extract.py now writes each extracted road or fill asset's
  ground offset into the schematic Offset field.
• engine/schematic_reader.py now reads the Sponge Offset field, and
  engine/road_schematic.py attaches that value to loaded tiles as
  ground_offset.
• engine/schematic_transform.py now preserves ground_offset when rotating a
  tile, so randomized fill-prop rotation does not lose the authored seat.

City construction

• pipeline/04_city_construct.py now seats the road grid from the shared road
  offset returned by the road schematic builder.
• Fill props are now seated from each tile's extracted ground_offset instead
  of from a hard-coded flush assumption.
• pipeline/03_grid_construct.py now preserves the road-grid offset when
  exporting the combined grid schematic.

Upgrade notes

• Re-extract road assets before rebuilding outputs. Existing road and fill
  schematics exported before 0.4.1 do not carry the new offset metadata, so
  they will still read as zero-offset assets until regenerated.
• After re-extraction, re-run the grid and city construction stages to pick up
  the corrected seating.

Verification

• python -m compileall src/engine/schematic_reader.py src/engine/schematic_transform.py src/engine/road_schematic.py src/pipeline/01_roads_extract.py src/pipeline/03_grid_construct.py src/pipeline/04_city_construct.py
• python src/pipeline/03_grid_construct.py --seed 1 --fine 8 --out .codex/grid_offset_smoke.schem
• python src/pipeline/04_city_construct.py --seed 1 --fine 8 --out .codex/city_offset_smoke.schem