description: "Per-game audit of Oblivion (TES4) compatibility — NIF v20.0.0.5 + the v10.x NetImmerse family, BSA v103, live ESM path" argument-hint: "--focus <dimensions>"

Oblivion Compatibility Audit

Deep audit of ByroRedux readiness for The Elder Scrolls IV: Oblivion content.

Architecture: Orchestrator. Each dimension runs as a Task agent (max 3 concurrent).

See .claude/commands/_audit-common.md for project layout, game-data locations, key reference docs, methodology, the path-reference convention, deduplication rules, and the base finding format. See .claude/commands/_audit-severity.md for the severity scale. Do not restate any of it here.

What Makes Oblivion Different (the audit surface)

Oblivion is the oldest title in the lineage and exercises code paths no other game reaches. Two NIF eras coexist in vanilla Oblivion - Meshes.bsa:

The retail body — NIF v20.0.0.5 (bsver=11): inline strings, u16 flags, no per-block size table. This is what most clutter / architecture / creature meshes are.
The NetImmerse tail — a long tail of v10.x sub-versions (down to pre-Gamebryo v3.3.0.13) authored years earlier. These have subtly different field layouts gated by tight version bands in nif.xml, and — like v20.0.0.5 — no block_size table, so a single N-byte under-read truncates the entire downstream subtree.

The v10.x tail is the Oblivion-unique risk. Retail FO3/FNV/Skyrim are all BS202 / 20.x and never touch these bands; a regression here is silent and Oblivion-only. The v10.x stride-drift family (#1506 NiInterpController / NiQuatTransform, #1507 NiPSysData + emitter, #1508 NiBlendInterpolator + ControlledBlock, #1509 NiGeomMorpherController bsver > 9 gate) is resolved as of 2026-06-13; Oblivion-Meshes went from 56 truncated → 6 (further reduced by #1543/#1544, regenerated baseline #1611). This audit treats that family as a regression-guard set, not open work.

| Aspect | Current state (verify, don't trust this table blindly) | |-------------------|--------------------------------------------------------------------| | NIF format | v20.0.0.5 retail + v10.x NetImmerse tail (both sizeless) | | BSA format | v103 — opens AND extracts cleanly across all vanilla archives (regression guard, #699) | | ESM parser | Live — crates/plugin/src/esm/ with parse_esm_cells walker + ~25 record types, several with Oblivion-specific decode branches. NOT a stub (the per-game legacy/tes4.rs stub was removed under #390). | | Parse rate | See ROADMAP.md Oblivion compat-matrix row (drifts after each sweep; do NOT hardcode a number here). Post-v10.x-family + #1543/#1544: 6 residual NetImmerse truncations (checked-in oblivion_truncations.tsv baseline, #1611) + 1 corrupt-by-design hard-fail (#698 closed). | | Cell loading | Interior renders end-to-end (Anvil Heinrich Oaken Halls). Exterior blocked on TES4 worldspace + LAND wiring (same shape FO3 was — not BSA v103) | | Reference data | /mnt/data/SteamLibrary/steamapps/common/Oblivion/Data/ |

Known Quirks (do NOT re-derive — verify still hold)

user_version only exists for files ≥ v10.0.1.8. Older NetImmerse files have num_blocks where user_version would be. Confirm the version >= NifVersion::V10_0_1_8 guard in crates/nif/src/header.rs.
BSStreamHeader presence is the nif.xml dual-band condition (post-#170), NOT the old version == 10.0.1.2 || user_version >= 3. The live guard is version == V10_0_1_2 || (user_version >= 3 && (version ∈ {V20_2_0_7, V20_0_0_5} || (V10_1_0_0 <= version <= V20_0_0_4 && user_version <= 11))). A v20.0.0.5 Oblivion file with user_version >= 3 reads the header; a non-Bethesda file outside the band must NOT (regression of #170).
NiTexturingProperty reads a uint count directly — do NOT add a leading Has Shader Textures: bool. nif.xml is wrong here; the Gamebryo 2.3 source is authoritative. Regressing this breaks every Oblivion clutter / book / furniture mesh. Test lives in crates/nif/src/blocks/properties_tests.rs.
Oblivion has no per-block size table. A single mis-aligned read poisons every subsequent block — there is no block_size-advance recovery path (unlike 20.2.0.7+). This is why every v10.x stride-drift bug truncated whole subtrees rather than one field.
Pre-Gamebryo v3.3.0.13 files (e.g. meshes/marker_*.nif) inline type names as sized strings instead of a global type table. Parser returns an empty NifScene with a debug log rather than failing.
NetImmerse v10.x leading group_id. For versions in [10.0.0.0, 10.1.0.114), each block is preceded by a 4-byte group_id (00 00 00 00); block content starts AFTER it. Mixing stream-relative vs file offsets is the classic false-trail when chasing stride drift (see memory note nif_v10x_stride_drift_resolved).
as_ni_node walker must unwrap every NiNode subclass (BSOrderedNode, NiBillboardNode, NiSwitchNode, NiLODNode, …) so scene-graph walks descend correctly.

Parameters (from $ARGUMENTS)

--focus <dimensions>: Comma-separated dimension numbers (e.g., 1,3). Default: all 7.

Phase 1: Setup

Parse $ARGUMENTS.
mkdir -p /tmp/audit/oblivion.
Fetch dedup baseline: gh issue list --repo matiaszanolli/ByroRedux --limit 200 --json number,title,state,labels > /tmp/audit/issues.json.
Confirm Oblivion/Data/ exists; if not, note which dimensions lose real-data validation.
Read the current Oblivion row in ROADMAP.md (compat matrix) and docs/feature-matrix.md so every status claim cites live numbers, not this file.

Phase 2: Launch Dimension Agents (parallel)

Dimensions are ordered by Oblivion-specific risk: NIF version handling first (the v10.x tail is the unique surface), then archive, ESM, render, real-data.

Dimension 1: NIF Version Handling — v20.0.0.5 + the v10.x NetImmerse Tail

Subagent: legacy-specialist Entry points: crates/nif/src/header.rs, crates/nif/src/version.rs, crates/nif/src/stream.rs, crates/nif/src/blocks/, docs/legacy/ Checklist:

user_version threshold (V10_0_1_8) and the BSStreamHeader dual-band guard in header.rs match nif.xml (see Known Quirks). The #170 regression test in crates/nif/src/header.rs (tests module) must still assert a non-Bethesda out-of-band file does NOT read the header.
The v10.x sub-version constants exist and are used as gate boundaries: V10_0_1_2, V10_1_0_0..V10_1_0_114, V10_2_0_0, V20_0_0_4, V20_0_0_5 in crates/nif/src/version.rs.
#1509 regression guard (crates/nif/src/blocks/controller/morph.rs): NiGeomMorpherController gates its trailing field on bsver > 9 (NOT the old bsver != 0 && bsver <= 11). doghead.nif is v10.2.0.0 bsver 9 and must skip the trailing field; Oblivion's bsver-11 morph rigs (e.g. obgatemini01.nif) must keep it — an off-by-band gate either direction truncates/misaligns NiMorphData. Tests: crates/nif/src/blocks/controller/path_lookat_tests.rs.
#1506/#1507/#1508 regression guards — the resolved stride-drift family. Each was a since/until field gated on the wrong comparator dropping N bytes. Confirm NiInterpController/NiQuatTransform, NiPSysData + emitter, and NiBlendInterpolator + ControlledBlock all still land exactly on the next block boundary in the v10.x bands. Any new truncation growth on Oblivion-Meshes is a regression of this family — escalate, don't re-derive.
NiTexturingProperty reads u32 count raw, no bool gate (regression guard).
Inline-string block-type handling for pre-v3.3.0.13.
u16 vs u32 flag width per block in the v20.0.0.5 vs v10.x layouts.
Oblivion-only / legacy block types dispatched in crates/nif/src/blocks/mod.rs: NiKeyframeController, NiSequenceStreamHelper, NiBillboardNode + NiNode subclasses, NiLight hierarchy, NiUVController, NiCamera, NiTextureEffect, the legacy particle stack, the BSShader*Property aliases.
Collision import (crates/nif/src/import/collision/mod.rs): BhkMultiSphereShape and BhkConvexListShape translate into CollisionShape (the former to Ball/Compound, the latter to ConvexHull/Compound) via resolve_shape_inner in the extract_collision chain — they must not fall out silently. Verify against the BhkMultiSphereShape / BhkConvexListShape downcast arms.
bhk motion_type via the canonical Havok enum (#1652, dc33ec7d): collision.rs::havok_motion_type maps the raw hkMotionType byte per the full nif.xml enum (1–5/8 → Dynamic, 6 KEYFRAMED → Keyframed, 7 FIXED → Static, 9 CHARACTER → CharacterKinematic, 0/other → Static); the pre-fix 4 => Keyframed / _ => Static collapse froze BOX_INERTIA (4) clutter. Shared with FNV/FO3 — re-introducing the collapse is the regression. Output: /tmp/audit/oblivion/dim_1.md

Dimension 2: BSA v103 Archive

Subagent: general-purpose Entry points: crates/bsa/src/archive/ (mod.rs, open.rs, extract.rs, hash.rs) Checklist: This is a regression guard — v103 decompression has worked end-to-end since 2026-04-17 (#699); the "v103 is broken" premise is dead, do not regenerate it.

BSA_V_OBLIVION = 103 recognised in open.rs; rejection only outside {103,104,105}.
Folder-record size: v103 AND v104 are 16 bytes; only v105 (Skyrim SE) is 24. The live code is if version == BSA_V_SKYRIM_SE { 24 } else { 16 } in open.rs. (The older skill text claiming "v104 = 24 B" was wrong — verify against the constant, do not perpetuate it.)
v103 archive-flag semantics (e.g. the "Xbox archive" bit several vanilla v103 archives set, ignored for embedded names — embed_file_names gates on >= BSA_V_FO3_SKYRIM).
Folder/file hash function in hash.rs still produces correct hashes.
Full-archive sweep stays at 100% extraction. Only escalate to an open finding if meshes/*.nif extraction starts failing on a previously-clean archive. Output: /tmp/audit/oblivion/dim_2.md

Dimension 3: ESM Record Coverage (live path, not a stub)

Subagent: general-purpose Entry points: crates/plugin/src/esm/ (mod.rs, reader.rs, cell/, records/) Checklist: TES4 records share the live ESM path with FNV/FO3 — there is no per-game stub (removed under #390). The parser already carries Oblivion-specific decode branches; the audit's job is correctness + coverage gaps, not "does it exist".

TES4 header (HEDR version 1.0 vs 0.94) and GRUP structure handled by the walker (crates/plugin/src/esm/records/grup_walker.rs).
Oblivion-specific branches already present — verify they're correct, not regressed: flags_oblivion + is_oblivion in crates/plugin/src/esm/records/actor/mod.rs (split from actor.rs, #2055); MGEF-by-code map (Oblivion 4-char effect codes) and the CONT 4-byte-payload guard in crates/plugin/src/esm/records/tests.rs / container.rs; CLMT three-entry WLST in crates/plugin/src/esm/records/climate.rs.
16-byte ACBS guard (#1650, 3d5d0d68): Oblivion NPC_/CREA ship a 16-byte ACBS (flags u32 @0, level i16 @10) — distinct from the ≥24-byte FNV/FO3/Skyrim layout, so parse_npc (actor.rs) needs a GameKind::Oblivion arm gated on len >= 16 before the FNV arm. Pre-fix the ≥24 arm never fired on Oblivion: record.level defaulted to 1 (high-level NPCs resolved lowest-tier inventory) and acbs_flags defaulted to 0 (every actor read Male via Gender::from_acbs_flags). Tests: oblivion_16byte_acbs_parses_level_and_gender
- fnv_ignores_16byte_acbs in actor.rs/tests.rs. Per-game layout must stay gated at the parser→record boundary, never re-derived at spawn/equip time.
The two ignored Oblivion real-data parity tests (clas_oblivion_knight_against_vanilla, race_oblivion_data_and_subs_against_vanilla) still pass against vanilla Oblivion.esm when un-ignored.
CELL walker: does parse_esm_cells (crates/plugin/src/esm/cell/mod.rs) handle Oblivion's CELL group layout (XCLL lighting, RCLR, interior vs exterior block grouping)?
DIAL/INFO format differs between Oblivion and later titles — does the conversation-tree decode (M24.2) account for it, or silently mis-read?
What is the minimum record set the cell loader needs to place an Oblivion exterior REFR? (Feeds the Blocker Chain.) Output: /tmp/audit/oblivion/dim_3.md

Dimension 4: Rendering Path for Oblivion Shaders

Subagent: renderer-specialist Entry points: crates/nif/src/import/material/ (mod.rs, walker.rs, shader_data.rs), crates/nif/src/import/walk/, byroredux/src/systems/particle.rs, crates/renderer/shaders/triangle.frag Checklist:

NiTexturingProperty → MaterialInfo pipeline (base slot 0, dark slot 1, normal-from-bump per #131, detail, glow, gloss).
NiMaterialProperty color mapping is raw monitor-space (per 0e8efc6 — do NOT srgb_to_linear legacy colors).
NiAlphaProperty blend-factor extraction routes every Gamebryo AlphaFunction enum value.
NiStencilProperty / NiZBufferProperty / NiVertexColorProperty / NiSpecularProperty / NiWireframeProperty / NiDitherProperty / NiShadeProperty — honored or dropped silently? #869 guards: NiWireframeProperty wires to the LINE pipeline variant; NiShadeProperty.flat_shading is consumed in the fragment shader.
Vertex-color interaction with material color.
#1239 Oblivion NiPSysEmitter version gating: Oblivion's pre-Skyrim emitter field layout is routed via nif.xml's version gate — a regression silently misparses emitter authoring.
Typed particle-emitter import → runtime path: NiPSysEmitter / NiPSysEmitterCtlr / NiPSysEmitterCtlrData / NiPSysGrowFadeModifier are TYPED blocks (crates/nif/src/blocks/particle.rs) decoded by extract_emitter_params + extract_emitter_rate (crates/nif/src/import/walk/mod.rs) and fed into apply_emitter_params (byroredux/src/systems/particle.rs). Verify an Oblivion emitter that parses (per the #1239 gate) actually reaches the ECS authoring path and animates — not just parses-then-drops.
Disney BSDF gating regression guard (#1248-#1252): zero Oblivion materials author BGSM/.mat, so MAT_FLAG_PBR_BSDF (crates/renderer/shaders/include/shader_constants.glsl) must be 0 across the entire Oblivion material universe — the Disney lobe (crates/renderer/shaders/include/pbr.glsl) is unreachable for Oblivion. Any Oblivion scene activating Burley / anisotropic GGX is a gate regression. Output: /tmp/audit/oblivion/dim_4.md

Dimension 5: NIFAL Canonical Material Translation for Oblivion

Subagent: renderer-specialist Entry points: byroredux/src/material_translate.rs, crates/nif/src/import/material/walker.rs, crates/core/src/ecs/components/material.rs, byroredux/src/render/static_meshes.rs, docs/engine/nifal.md Checklist: Trace an Oblivion NiTexturingProperty/NiMaterialProperty MaterialInfo through the single canonical boundary translate_material (byroredux/src/material_translate.rs) into the ECS Material.

Metalness/roughness arrive as plain f32 carrying the f32::NAN sentinel (mesh.metalness_override/roughness_override .unwrap_or(f32::NAN)) and are resolved exactly once by Material::resolve_pbr (crates/core/src/ecs/components/material.rs). Confirm no per-draw classify_pbr reappears and that static_meshes.rs still reads m.roughness/m.metalness directly with no render-time keyword scan.
emissive_source is tagged EmissiveSource::Material for Oblivion legacy meshes via the NiMaterialProperty arm in crates/nif/src/import/material/walker.rs (distinct from the Skyrim/FO4 BSLightingShaderProperty arm). Test: crates/nif/src/import/material/emissive_source_tests.rs.
MAT_FLAG_PBR_BSDF stays 0 across the all-legacy Oblivion universe (shared with Dim 4's Disney-gate guard; flag this once, cross-reference). See /audit-nifal for the cross-game canonical-tier audit; this is the Oblivion-specific slice. Output: /tmp/audit/oblivion/dim_5.md

Dimension 6: Real-Data Validation

Subagent: general-purpose Entry points: crates/nif/examples/nif_stats.rs, crates/nif/examples/recovery_trace.rs, crates/nif/tests/parse_real_nifs.rs, crates/nif/tests/per_block_baselines.rs Checklist:

Run nif_stats (and nif_stats --tsv for the per-type histogram) over Oblivion - Meshes.bsa; compare clean/recovered/truncated counts against the current ROADMAP Oblivion row AND the checked-in Oblivion baseline in per_block_baselines.rs. Any unknown growth or parsed shrinkage is a regression.
Run recovery_trace to enumerate the residual truncated files (6 NetImmerse v10.x markers — marker_arrow/divine/map/radius/temple/travel — per the checked-in oblivion_truncations.tsv baseline, #1611, post-#1543/ #1544). Confirm they're the expected NetImmerse tail and the single corrupt-by-design hard-fail, not new drift.
Cross-check the block-type histogram for any new types appearing since the last sweep.
Pick 3 representative interior meshes (Anvil Heinrich Oaken Halls chandelier, a book, a creature head) and trace them through import_nif_scene → verify expected mesh count + material chain. Output: /tmp/audit/oblivion/dim_6.md

Dimension 7: Exterior Blocker Chain & Game-Specific Quirks

Subagent: general-purpose Entry points: ROADMAP.md (Known Issues + compat matrix), docs/feature-matrix.md, byroredux/src/cell_loader/, docs/audits/ Checklist:

The real exterior blocker is TES4 worldspace + LAND wiring (same shape FO3 was pre-cell-loader) — not BSA v103 decompression, which has worked end-to-end since 2026-04-17 (#699). Do not regenerate the dead "v103 is broken" framing.
Does the --bsa CLI path open + list + extract Oblivion archives end-to-end?
Are there Oblivion-specific record types the cell loader (byroredux/src/cell_loader/) needs beyond the FNV-aligned set to place exterior REFRs?
Animation blocks that parse but can't play because scene-graph name resolution is missing?
Does the pre-v3.3.0.13 fallback log at warn or debug (spam risk on full-archive sweeps)?
Any 100%-parse NIFs that would still render wrong (legacy particle emitters that parse but don't route to the renderer — cross-check Dim 4)?
_far.nif distant-object LOD (#1726/#1745, Session 52) — verify the Oblivion/FO3/FNV placement scheme + real LOD textures still resolve on Oblivion exteriors; entry points cell_loader/object_lod.rs, cell_loader/placement_lod.rs. Output: /tmp/audit/oblivion/dim_7.md

Phase 3: Merge

Read all /tmp/audit/oblivion/dim_*.md files.
Combine into docs/audits/AUDIT_OBLIVION_<TODAY>.md with structure:
- Executive Summary — Current compatibility level (NIF parse incl. v10.x tail, archive extract, ESM parse, render end-to-end), top blockers in priority order. Cite ROADMAP/feature-matrix numbers, not this skill.
- Dimension Findings — Grouped by severity per dimension.
- Blocker Chain — Sequential list to reach "exterior cell renders". Interiors already work end-to-end (Anvil Heinrich Oaken Halls). Real chain: TES4 worldspace + LAND wiring → CELL exterior REFR placement → exterior bench. Do NOT regenerate the stale BSA-v103 framing.
- Regression Guard List — Previously-fixed items this audit verified still hold: the v10.x stride-drift family (#1506/#1507/#1508/#1509), NiTexturingProperty u32 count, BSStreamHeader dual-band (#170), user_version threshold, BSA v103 extraction (#699), Disney-gate stays 0.
Remove cross-dimension duplicates.

Suggest: /audit-publish docs/audits/AUDIT_OBLIVION_<TODAY>.md

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