Build the atom KIT "medieval-cathedral": a Gothic cathedral (13th c.) made of SLICE MODULES that code joins along X:
cath_west_front (twin towers, 3 portals, rose window), cath_nave_bay (repeated 5-8 times; also used for the choir),
cath_crossing (with lantern tower), cath_transept_bay + cath_transept_end (on both sides, +Z and -Z, mirrored by the
code), cath_apse (polygonal chevet), cath_tower_spire (optional spire on a west tower). Reference: sheet.jpg here (St
Michael's priory study: flying buttresses with pinnacles, lancet and tracery windows, rose window, portal with
archivolts, crossing tower, slate roofs, dressed limestone). Your dir: /root/fal-author/medieval-cathedral-v1/ on gex44
(here: ~/forge-build/forge-assets/jobs/medieval-cathedral-v1/).
Atoms, cross-section and origins: SETTLEMENT.md section 1, medieval-cathedral table. Slices MUST join seamlessly:
walls, eaves, roof planes, ridge, aisle roofs and the buttress rhythm continue exactly from one cath_nave_bay to the
next and into the crossing, west front and apse. Roofs baked in (slate courses or lead sheets, real thickness).
Window tracery: geometry for the rose and the big windows (one tracery mesh reused via instancing in Blender is fine;
export as part of the atom), Leaded_glass behind it. It is seen from 30-200 m in a game: silhouette, depth and rhythm
matter more than tiny carving. Triangle budget (overrides the contract numbers): whole kit <= 160k; west front <= 35k,
nave bay <= 14k, others <= 20k. The contract's roof-cover and eaves sections do NOT apply. test_house.png: assemble a
full cathedral (west front + 2 spires, 5 nave bays, crossing, 2 transept bays + end on each side, 2 choir bays, apse)
and render a 3/4 view from the north-west and a south elevation. No visible seams.
DETAIL LEVEL: match ~/forge-build/forge-assets/jobs/medieval-atom-kit-v1/ (read its kit_sheet.png, runtime_*.png and
build_kit.py, read-only): same shelf material NAMES where they apply (Rubble_stone, Rubble_stone_dark, Oak_frame,
Oak_frame_grey, Plaster_ochre/white/pink, Clay_tile, Clay_tile_dark, Dressed_limestone, Wrought_iron, Leaded_glass,
Door_paint, Sign_paint) so one village shares one look; add new materials only when needed (names in CamelCase_words).
The interface (atom names, sizes, origins) is FROZEN in ~/forge-build/forge-assets/omg/kit/building/SETTLEMENT.md
section 1: read it; code is being written against it right now, in parallel. Put every atom's real bounding box and any
sockets (attach points) in kit.json. Low-poly where it does not show, real shapes where it does (arches, mouldings,
tracery read as geometry at 10-30 m). Phone budget matters: no subdivided flat walls; one material per surface type.