Build heavy space cruiser in wet-navy battleship style: a long ship-like hull with a sharp flared bow, a stepped bridge superstructure, three triple-barrel main gun turrets on top and one under the hull, secondary twin turrets along the flanks, missile batteries, a big engine cluster at the stern (the one on sheet.jpg) as a production, REALISTIC 3D game asset in Blender, for Forge's asset library. Look at the reference
images in this directory with your image tool first: sheet.jpg. It must look like a real object from a modern
third-person game up close: never blocky, never toy-like, never flat colours.

Blender 5.2 is headless on another machine. Write bpy scripts here and run them with:
  ssh gex44 /root/blender-spike/blender-5.2.0-linux-x64/blender -b --python-exit-code 1 --python /root/fal-author/heavy-cruiser-naval-v1/<script>.py
(first `ssh gex44 mkdir -p /root/fal-author/heavy-cruiser-naval-v1`, scp scripts and any textures to gex44:/root/fal-author/heavy-cruiser-naval-v1/, scp renders back here, then
LOOK at them with your image tool). Iterate until the renders match the references: silhouette, proportions, every
named part, materials. Only one Blender job on the GPU box at a time from you.

Quality bar:
- Real dimensions in metres: 450 m long, 70 m wide, 90 m high.
- Construction detail as geometry where it shapes the silhouette or catches light: bevelled edges everywhere (no razor
  box edges), real thickness, frames around openings, trims, rails, fittings, bolts, ropes, cables, small parts. No
  z-fighting, no gaps, nothing floating, smooth shading on round parts.
- Photographic materials: use CC0 Poly Haven textures (download 1k or 2k jpg maps from https://dl.polyhaven.org/file/
  ph-assets/Textures/jpg/<res>/<id>/<id>_<map>_<res>.jpg, maps diff, nor_gl, arm; pick ids by browsing
  https://api.polyhaven.com/assets?t=textures) mixed with node detail (rust streaks, grime, moss, edge wear, salt), then
  BAKE each material's result with Cycles to image textures (base colour, normal, ORM) so it survives glTF export.
  List every Poly Haven id you used in NOTES.md (licence evidence). No other image sources.
- Budget: 80k to 200k triangles, at most 9 materials, texture images at most 2048 px, GLB at most 12 MB.

Export contract (glTF binary .glb, Y up, metres): Nose toward +Z, up = +Y, +X = the ship's LEFT side, centred on X = 0; origin (0,0,0) at the ship's centre of mass (about the middle of the hull), the ship level and flying: landing gear, if the design has any, is RETRACTED with its doors closed. Apply transforms and modifiers. No cameras, lights or
helpers in the GLB. GAME WEIGHT overrides the budget above: every texture image at most 1024 px, ORM / occlusion maps at most 512 px; share baked texture sets between parts and use tiling materials + trim textures on big surfaces. BIG SHIP: a 1024 bake cannot hold a hull this size: use tiling hull-plate materials and trim textures (panel strips, window strips, vents) with world-scale UVs. Detail must read at three distances: the silhouette (big masses, towers, engine blocks), the middle (superstructure, turrets, hangar mouths, antenna forests, armour belts) and close up (greebles, pipes, panel seams, rows of lit windows at human scale). Small parts may be instanced/linked duplicates. Separate named mesh nodes: Hull (everything fixed to the hull). Every MOVING part is its own node with its object origin ON its pivot: Turret_1..Turret_n (each gun turret, origin on its vertical traverse axis, turns about its local Y) each with a child Gun_1..Gun_n (the barrels, origin on the elevation trunnion axis, elevates about X); Canopy (cockpit canopy, origin on its hinge) on craft with a canopy; and the extra moving parts named in the description. Empty nodes (no mesh): Thruster_1..Thruster_n at the centre of every main engine nozzle exit (games put flame and glow there; exhaust points to -Z), Muzzle_1..Muzzle_n at every barrel tip (child of its Gun, or of Hull for fixed guns), Hardpoint_1..n (missile and torpedo launch points), Seat_Pilot (pilot hip point) on craft with a cockpit, Camera_Chase (a good third-person chase camera point behind and above), Light_Nav_L (left tip, red), Light_Nav_R (right tip, green), Light_Beacon. Materials: the glowing inside of every engine nozzle = one material named "Engines" (emissive, colour as described, modest strength, games raise it); lit windows, running lights and glowing details = one material "Lamps" (emissive); cockpit or bridge glazing = one material "Glass" (alpha BLEND, tinted) with a visible cockpit (seat, panels, stick) behind it on small craft. In nodes.json add "axes": for every moving node, the unit axis it turns about in its parent's space. PAINT CONTRACT (how games get faction colours of one model): the main hull colour lives in ONE material named exactly "Paint". Its base colour TEXTURE holds only light neutral detail (near white, with panel lines, grey grime, engine scorch, micro-meteorite pitting and chipped edges baked in) and its baseColorFactor holds the paint colour; default factor = [0.32, 0.34, 0.36] (dark grey). A game changes that factor, so nothing else (bare metal, engines, glass, lamps, weapons, cockpit) may use Paint. In nodes.json add "paints": six good paints for this model as linear RGB triples with names, the default first, in the spirit of: naval grey, gunmetal, olive drab, desert sand, arctic white, deep navy, black, crimson; and render paints.png: a 3x2 grid of the same 3/4 view in those six paints (EEVEE or low-sample Cycles) to prove the recolour works. MOVING PARTS: never apply transforms to a moving node. Check it in Blender before export: rotate each moving node 30 degrees in a test render; nothing may leave its place. No text, numbers, insignia, faction emblems, flags or logos anywhere (games add their own factions). ORIGINAL DESIGN: never model a famous film, TV, anime or game ship (no X-wing, TIE, Star Destroyer, Millennium Falcon, Enterprise, Serenity, Normandy, Viper, Valkyrie, Gundam, Halo, Homeworld, EVE, Elite or Expanse ship): if the sheet looks like one, keep its proportions and parts but make the silhouette details, nose and engines your own. RENDERS: final.png and paints.png on a dark space backdrop (near black with a faint blue gradient, no ground) lit by a strong white key light from the upper front left plus a soft cool fill, so every part reads. Keep this directory clean: put any helper tools you install (node_modules, vendored three.js, browser checks) under /tmp, never here. Pace: deliver a first complete GLB within about 40 minutes, then use what is left of about 80 minutes to improve what the renders show is weakest. Use Cycles with the GPU (OptiX/CUDA) and modest samples for bakes and renders. 
Deliver in this directory: heavy-cruiser-naval.glb; build_heavy-cruiser-naval.py (ONE script that builds the whole asset from an empty scene,
downloads/loads its textures, bakes and exports: the GLB you deliver must come from a clean run of it); final.png
(1920x1080 Cycles render, 3/4 front view, soft daylight); side.png (orthographic side); clay.png (same view as final,
plain grey material); nodes.json (every node name with world position + overall bounding box); NOTES.md (6 lines:
what you made, triangle count, materials, texture sizes, Poly Haven ids, what still differs from the references).
Stop when you judge it matches the references and would not look out of place in a modern realistic game.