gig-line/MEMORY.md

MEMORY.md

Shared working memory between sessions and collaborators. Short, dated entries with evidence: the command, the log line, or the file path.

Scope: facts and traps that cost time to establish. Planned work lives in ROADMAP.md; formal setup, pins, and licensing live in Docs/.

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2026-11-07 — Unreal Engine 5.8.4

• Extracted to /run/media/system/DATA/Engines/UE_5.8.4 (73 GiB, unzip exit 0). CL 58902052, ++UE5+Release-5.8.
• Gotcha: the editor needs a writable ~/.config/Epic. In the agent shell it crashed with signal 11 twice and looked like a broken install. The log named it: create dir('/home/zwitschi/.config/Epic/') failed: errno=30 (Read-only file system) → Fatal error: Failed to create Intermediate directory '…/.config/Epic/UnrealEngine/5.8/Intermediate/'. Rerunning with HOME=/tmp/uehome XDG_CONFIG_HOME=/tmp/uehome/.config reached LogInit: Display: Engine is initialized.
• Vulkan RHI is still unproven. The successful run used -NullRHI. Untested: UnrealEditor -vulkan from a desktop terminal.
• A packaged game does not need ~/.config/Epic, so this failure does not follow the build.

2026-11-07 — Agent shell limits

• The agent shell has a read-only home and read-only /run: sudo is blocked (no new privileges), flatpak run and podman cannot create instances, /dev/nvidia* is absent so nvidia-smi always fails there. None of this is a broken machine; verify GPU things from a normal terminal.
• Anything outside the session workspace (/run/media/system/DATA/Engines, /tmp) needs the wider sandbox with an approval prompt.

2026-11-07 — Reference photography

• Licensing is not a gate for local development. Reference images live in the gitignored Art/reference/ and are never committed. What each set establishes is written into Docs/reference-notes-hollywood.md.
• Commons text search runs dry; categories do not. Tools/commons_fetch.py --category "Category:Hollywood Masonic Temple" surfaced 15 files a search never showed, including 4–5k px façades.
• upload.wikimedia.org throttles hard. Batches of six or fewer with --delay 3; a throttled file is skipped and recorded rather than killing the run (HTTP 429).
• Unqualified queries return junk. Hollywood Boulevard shops returned a Münster street, Hollywood Masonic Temple entrance a Seattle card index. Check the hit list before accepting a set.
• OpenRouter web search is expensive. One gpt-5.2 + openrouter:web_search call ran 17 searches and cost $0.38; two of its eight URLs were Commons files already held. Use it for a known gap, not a sweep. Tools/page_image_fetch.py turns results into files by reading og:image.
• The inherited "eight stone steps, 12 m wide" is wrong. Photographs show three portals, each with its own short flight. Do not copy that number into geometry.

2026-11-06 — Blender and Blosm, headless

• flatpak run does not work here. Call the binary inside the app tree: B=/var/lib/flatpak/app/org.blender.Blender/x86_64/stable/active/files, then LD_LIBRARY_PATH="$B/blender/lib" "$B/blender/blender" -b … with BLENDER_USER_SCRIPTS="$HOME/.var/app/org.blender.Blender/config/blender/5.2/scripts".
• Blosm needs two headless workarounds, both already in Tools/blosm_blockout.py:
  1. it refuses to import until an asset directory is set, and the check fires before the mode is honoured;
  2. in background mode the default level table is empty, and the add-on then takes a path with a broken relative import (from gui import addDefaultLevels). Seeding one entry avoids it.
• Blosm projects on a sphere, not an ellipsoid. Its frame is about 0.4 % oversized and rotated by meridian convergence — roughly 2 m at the theatre. Fixed with a six-parameter affine into EPSG:26911 (0.0 cm residual).
• Transform roots only. 256 of 275 objects are children; transforming both parent and child applies the correction twice and reads as a 2 m placement error.
• Blosm quietly fetches from Overpass for relation members missing from the extract. loadMissingMembers is off by default in the tool so imports stay offline and reproducible.

2026-11-06 — Geo data traps

• The 3DEP export is a tiled TIFF, not strips. A strip reader silently scrambles rows and produces fake 0 m / 127 m bands. Geo/scripts/dem_stats.py handles tiles.
• Sample walk routes through PROJ. Placing samples with the OSM spherical approximation put them metres off the UTM meshes and reported 91 phantom holes. /tmp is not shared between tool calls here either — regenerate instead of saving intermediate files there.
• 3DEP cannot resolve kerbs. Sharpest break near the kerb line is 0.09–0.12 m/m, a gutter transition, not a 0.15 m upstand. Kerb height stays a stated assumption.
• Building interiors are not ground. Points inside the hero footprint returned 114.5–117.1 m — structure, not terrain. Excluded from the relief figure.
• Two measurements independently agree on the carriageway: crossing length 20.9 m and gutter spacing −10 / +10…12 m.

2026-11-06 — Repository traps

• Without git lfs install the lfs filter is inactive and git add does not warn — it stores the file as a plain blob. Tools/check-lfs.sh is the guard.
• Never commit reference images or .env. .gitignore covers /Art/reference/, .env, *.env. When images slipped in early, history was rewritten to remove them.
• The project origin is Hollywood × Highland: E 376 515.389 / N 3 774 224.083 in EPSG:26911. Blender X east, Y north, Z up, metres, Z measured from the origin ground (NAVD88 115.911 m). The whole block sits at negative X.

2026-11-07 — Unreal pipeline findings

• UE 5.8 game targets must use BuildSettingsVersion.V7 to share the installed editor's build environment; V5 is rejected with "modifies the values of properties … not allowed".
• UnrealEditor-Cmd -run=pythonscript swallows Python print() with -stdout in 5.8 — write results to a file instead (see Tools/ue_scale_test_import.py).
• unreal.Box has min/max, not origin/get_extent() in 5.8 Python; compute centre/size from the corners.
• FBX Blender→UE axis mapping is east→+X, north→−Y, up→+Z with preset ue_metric_v1; the Y mirror is inherent (RH→LH). Compass math in game code: north = −Y. Verified with the three-cube scale test.
• Headless asset import works fine with -nullrhi; unreal.AssetImportTask + FbxImportUI is the pattern (Interchange pipeline under the hood).
• Flatpak Blender headless needs XDG_CONFIG_HOME=$HOME/.var/app/org.blender.Blender/config for extensions: bpy.utils.user_resource('EXTENSIONS') otherwise resolves to ~/.config/blender/5.2/extensions (empty) and bl_ext.blender_org.mpfb is undiscoverable. Blosm unaffected (scripts/addons via BLENDER_USER_SCRIPTS). Found via Tools/addon_compat_probe.py; documented in Art/blender/README.md.
• UE 5.8 Interchange skips material/texture assets for skeletal FBX imports (static imports do get materials). Finish the chain in Python: import texture, build Material via MaterialEditingLibrary, assign with sm.set_editor_property('materials', [SkeletalMaterial]) — the struct field is material_interface, not material, and SkeletalMesh.set_material() does not exist. See Tools/ue_character_import.py.
• Blender 5.2 FBX exporter removed armature_nla (passes for 4.x recipes fail). Also: a baked image is only referenced by the FBX exporter when image.filepath (not just filepath_raw) is set and the exporter can map the node — MPFB's v2 skin node-group tree can't be mapped, so a flat export material is required.

2026-11-07 — Collaboration and scope

• Two sessions edit this repo at once. The other session created the Unreal project and the blank package while this one was documenting. Check git log and git status before committing, and never git add -A blindly: it once swept generated Game/GigLine/Build/** logs into a commit. Stages the source files deliberately.
• Build/ under a project is generated, not source — FileOpenOrder/*.log and packaging output. .gitignore now covers it alongside Binaries/, Intermediate/, Saved/, DerivedDataCache/.
• Scope boundary for 0.1.0: do not tag v0.1.0 without an explicit go-ahead from the owner. It is a minor release and carries the walking/driving demo promise; the board's release checks decide when it is ready, not the pace of work.