zwitschi
a1d52aa583
Owner decision: prioritise realism, keep the performance target but put it last. - Quality goals reordered (01 + combined architecture.md): 1 visual realism, 2 geographic fidelity, 3 walkability/usability, 4 reproducibility/portability, 5 provenance, 6 performance efficiency. - Quality requirements (10 + combined) reordered to match, with two new realism requirements (façade reads like the photographs; placement within ~1 m) and the quality scenarios renumbered so QS-1 is the reference comparison and QS-9 the frame rate. - Both documents carry the same guard so the order cannot become an excuse: performance is a floor, not a preference - 60 FPS at 1440p without frame generation must be met at every release; if realism cannot fit, the realism scope is cut deliberately and recorded, never the frame rate. Walkability outranks realism in one direction: a block you fall through is not a demo. - Solution strategy and 'quality achievement' now lead with realism and describe performance as a budget rather than a driver. - Docs/release-checks.md: the performance check is the last check, with that reason stated; ROADMAP gains a 'Quality priority' section; AGENTS.md gains the tie-break rule beside the existing scope-cutting rule.
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Solution Strategy
Technology decisions
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Unreal Engine 5.8.4 for rendering, World Partition, physics (Chaos), and the Enhanced Input system. Chosen for its Linux support, open C++ source, and real-time rendering quality.
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Blender 5.2 LTS for all 3D modelling, UV work, and collision mesh authoring. Driven headlessly via
bpyPython scripts, not MCP. -
QGIS 4.2.3 for geographic data cleanup, coordinate conversion (EPSG:26911), and DEM preparation.
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Blosm 2.7.28 for OSM building and street blockouts inside Blender (layout data only — not authoritative façade, height, or pavement detail).
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MPFB 2.0.18 for human base meshes and baked materials (NPCs in
0.2.0+).
Top-level decomposition
The system is a single Unreal game module (GigLine) with no plugins beyond EnhancedInput. Content is organised by domain under /Game/Hollywood/:
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Site/— terrain, road, sidewalks, kerbs, crossing markings, site materials -
ElCapitan/— hero façade mesh and materials -
Frontage/— south-side block building meshes -
North/— north-side building meshes -
Input/— Enhanced Input actions and mapping context
All modelling and geographic processing live outside the game project in Art/, Geo/, and Tools/. The Game/ directory contains only engine-ready content and C++ source.
Quality achievement
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Realism first: reference photography and measured data drive every façade decision; renders are compared against the photographs with
Tools/visual_loop.py, and a façade is built from the shared 4.96 m module kit so the street wall reads consistently. Materials are authored in Unreal with world-aligned generated textures, and lighting is fixed daytime so a shot is comparable between runs. -
Performance as a budget, not a driver: dynamic-only lighting (no build step, no static shadow maps), world-space-noise materials (cheap procedural variation), minimal overdraw for street-level geometry, and a 60 FPS at 1440p floor that every release must meet. It closes the quality list because it constrains how much realism fits, not what the block should look like.
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Walkability: complex-as-simple collision on terrain (C++ helper forces the flag on the asset), block-all collision on every site mesh, swept transect QA verifies zero raycast holes.
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Fidelity: geographic data verified before modelling (footprints, bounds, DEM); building placement checked against street mesh, never in isolation; reference photography drives façade work.
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Reproducibility: pinned toolchain in
Docs/toolchain.md, named export presets,Tools/check-lfs.shgate, fresh-checkout build procedure inDocs/build.md.