# Cathedral rendering review — FABLE (2026-08-30)

Independent report-only review of the cathedral-terrace defect (falls
particles + marker stalks over terrain; landblock `0xF418`, camera in
`0xF4180104`/`0xF4180106`), baseline `37febd1f`, HEAD `bb9212c7`, branch
`claude/campaign-w-retail-frame-walk`.

**Evidence basis and honesty note.** Everything below marked with a citation
was read directly by this reviewer (oracle trace files, decomp pseudocode
docs + their byte-verification notes, commit messages/diffs, git topology,
ISSUES/register/memory docs, id-allocator source). Three deeper evidence
threads (fresh decomp re-reads of the alpha/particle path, a raw DAT parse
of `0xF418`, and the HEAD code-flow + probe-log audit) were dispatched but
had not returned when this report was due; every claim that depended on
them is explicitly marked **unverified**. Per the prompt's rule, unverified
is stated as unverified — nothing below is a plausible guess dressed as
fact.

---

## 1. Executive verdict (≤10 lines)

The six fixes failed because they accepted a false premise about WHERE this
scene's content sits in retail's frame. The posed oracle traces show that at
both defect poses retail's interior flood is EXACTLY ONE cell (`DC ov=1 n=1:
f4180104` / `f4180106`) — every other cathedral cell, including the falls'
stab-owner cells, draws as a *building look-in inside the landscape scope*,
pre-depth-clear, its alpha drained against full landscape depth
(`posed/terrace-center.log` F5, `posed/cathedral-arrival.log` F1-2;
`PView::DrawCells` @0x005a4840 model §5). Our pipeline instead treats the
whole complex as interior-flood content drawing post-clear, then tried to
rescue it with seals (slice 2) and a non-retail exit-plane-straddle
classifier (slices 4/5) that under-covers exactly the fully-outside falls
emitters. Fix = route every object's particles to its owner cell's actual
walk turn (look-in ⇒ landscape scope ⇒ pre-clear drain), delete the straddle
classifier, and re-land the quarantined marker-degrade port for the stalks.

---

## 2. Retail frame reconstruction (for an interior root with exit portals)

### 2.1 The frame skeleton — verified from the FW0 model + live traces

Source of truth used: `docs/research/2026-08-30-fw-walk-pseudocode.md`
(§1, §2, §3, §5, §9 — its seal loop, deferred z-clear, DEPTHTEST_ALWAYS,
punch-Z constants are recorded there as byte-verified against the raw
pseudo-C at `@0059a49af`, `@005a48a9`, `@0059be02`, `@0059bf4b`), the
extraction appendix `2026-08-30-fw-walk-pseudocode-appendix.md` (notably
the DrawBuilding/DrawMeshInternal full-sequence note at appendix line 811),
and the live cdb traces in `docs/research/2026-08-30-fw-walk-oracle/posed/`.

Order of one interior-rooted frame (`SmartBox::RenderNormalMode`
@0x00453aa0 → `PView::DrawInside` @0x005a5860 → `ConstructView` →
`PView::DrawCells` @0x005a4840):

1. **Flood** (`ConstructView(CEnvCell)` @0x005a57b0): view-driven — a
   neighbor cell enters `cell_draw_list` only if its portal polygon
   survives `PView::GetClip` @0x005a4320 against the current view (the ONLY
   CPU polygon clip in the frame). Exit portals
   (`other_cell_id == 0xFFFFFFFF`) raise `outside_view`.
2. **If `outside_view.view_count > 0`** (the traces' `ov`):
   a. `Render::PortalList = &outside_view`; **`LScape::draw`** @0x00506330
      — the whole landscape walk THROUGH the exit views: sky, terrain
      blocks far-to-near (view-CULLED per cell/block by
      `draw_check_blocks`' in_view union — **never view-clipped, never
      scissored**; `set_view` installs NO GPU state), buildings far-to-near,
      and — per building — the **look-in machinery**:
      `DrawBuilding` @0x0059f2a0 → BSP portal pass 1 punches apertures
      (`DrawPortalPolyInternal` flag=1: far-Z 0.999998987, DEPTHTEST_ALWAYS,
      z-write ON, alpha 0) → pass 2 recurses `ConstructView(CEnvCell)` +
      `DrawCells` (**`ov=0` — no landscape, no clear, no seals**) drawing
      look-in EnvCells + their objects into the punched aperture
      (appendix line 811). `DrawBuilding` itself calls
      **`FlushAlphaList(0f)`** before each building; `DrawBlock`
      @0x005a17c0 has the mid-walk pressure valve
      `FlushAlphaList(flush=0.75)` (appendix lines 700, 1027).
   b. **`FlushAlphaList(0f)`** — the pre-clear boundary drain: EVERYTHING
      queued during the landscape scope (terrain alpha, building alpha,
      look-in cell content alpha — and the particle polys of objects drawn
      in that scope) drains against **full landscape depth**. This is the
      drain that occludes the falls with terrain/water/trees.
   c. **Gated depth clear** (`if (forceClear || portalsDrawnCount != 0)
      Clear(z)`, model §5; `portalsDrawnCount` counts ONLY flag-0 seals —
      appendix line 811). Color is preserved; only depth clears.
   d. **Exit seals**: for the FLOODED cells' exit portals only,
      `DrawPortalPolyInternal(poly, 0)` — the portal's own projected depth,
      DEPTHTEST_ALWAYS, z-write ON, invisible (model §2, §5; byte-verified
      per model §9).
3. **Interior passes** (post-clear): `DrawEnvCell` far-to-near (BSP shells),
   then `DrawObjCellForDummies` (the flooded cells' objects) — depth
   accumulates fresh.
4. **Final drain**: `FlushAlphaList(0f)` back in `RenderNormalMode` — the
   flooded cells' alpha/particles drain against interior depth + the seals.

### 2.2 The four prompt questions

**(a) clipped vs culled vs whole.** CPU-clipped: ONLY the portal chain's own
polygon (`GetClip` @0x005a4320 — the model calls it "the only CPU polygon
clip in the frame"). View-culled (coarse sphere-vs-cone,
`Render::viewconeCheck` @0x0054c250, PARTIAL draws whole): objects.
Cell/block-granular culled (in_view interval grids): terrain blocks/cells.
Drawn whole with no per-view test: everything that passes those gates —
shells, meshes, particles. No GPU clip planes/scissor exist anywhere in this
frame (`set_view` = CPU globals only, model §6).

**(b) order relative to clear and seals.** PRE-clear: sky, terrain, water
(terrain-hosted — see §3, unverified detail), building shells, building
punches, **look-in EnvCell shells + look-in cell objects + their
emitters**, and all their alpha via the boundary drain. POST-clear: seals
first, then ONLY the root flood's EnvCell shells + objects + their
emitters, drained at the final flush. Seals draw exactly the flooded
cells' exit-portal polygons at own depth, color-write effectively off
(alpha 0), depth ALWAYS + write ON.

**(c) alpha list.** ONE list. Flush sites established from the docs:
per-building `FlushAlphaList(0f)` in `DrawBuilding` (appendix 811); the
`DrawBlock` pressure valve at `flush=0.75` (~2250 meshes, appendix 1032);
the `DrawCells` pre-clear boundary `FlushAlphaList(0f)` (model §5); the
`RenderNormalMode` end-of-frame `FlushAlphaList(0f)` (model §1). Depth in
place: landscape depth at the first three; interior + seal depth at the
final one. **Unverified:** an exhaustive caller enumeration of
`D3DPolyRender::FlushAlphaList` @0x0059d2e0 from the decomp itself, and
the exact particle-poly insertion path (the dispatched decomp read had not
returned; the MP2-era digest additionally records
`CPhysicsObj::ShouldDrawParticles` @0x0050FE60 = authored degrade range +
`cell->IsInView()`, from `claude-memory/project_render_pipeline_digest.md`).

**(d) depth at final-drain time.** Aperture pixels: the seal's own depth
(near the camera) — anything beyond the exits z-fails, so interior
particles cannot repaint the vista. Vista pixels visible through the
aperture ARE aperture pixels (the opening's polys); pixels covered by
interior geometry hold that geometry's depth. The falls are never in this
drain in retail at these poses — they drained pre-clear with the landscape.
**Unverified residual:** whether any visible vista pixel can lie OUTSIDE
the union of authored exit-portal polygons at the live chase camera (slice
6's observation implies yes for the WALK's clipped views; whether that
reflects portal-poly authoring or our clip is open — §8 Q1).

### 2.3 The live traces at the defect poses (decisive, read directly)

`posed/terrace-center.log` F5 (camera cell `f4180104` — the owner's
teleloc cell):

```
DI f4180104
DC pv=009d4e38 ov=1 n=1: f4180104     ← the interior flood is ONE cell
LS
BLD f518002e … BLD f4180014 BLD f418000a BLD f418000c BLD f418000b   (14 buildings)
```

`posed/cathedral-arrival.log` F1-2 (camera cell `f4180106`):

```
DI f4180106
DC pv=009d4e38 ov=1 n=1: f4180106     ← flood = root cell only
LS
BLD f3180020 … BLD f418000c
DC pv=009d4398 ov=0 n=2: f4180101 f4180100   ← look-in punch during LS
… BLD f418000b
DC pv=009d4398 ov=0 n=1: f4180104            ← 0xF4180104 IS A LOOK-IN
BLD f418000a
```

`posed/terrace-edge.log` F5 (outdoor root, camera cell `f418000b`): look-in
punches `n=1: f4180106`, `n=1: f4180101`, `n=1: f4180104` interleaved with
the building walk — no clear, no seals, everything drains against full
depth (why the owner sees a correct scene outdoors).

**Conclusion:** at the defect poses, `0xF4180104` and `0xF4180106` are in
DIFFERENT buildings' interiors (`f418000b` vs the `f418000a/c` group —
consistent with the "seam" being a building boundary), retail's interior
flood never crosses it, and ALL non-root cathedral cells + their stabs
compose in the landscape scope, pre-clear. The "toggles with which side of
the seam the camera is on" symptom is the root flip between these two
one-cell floods (and outdoor).

---

## 3. DAT geometry findings

**Verified:**

- The falls' observed particle owners `0x4F418012`–`0x4F418015` decode per
  `src/AcDream.Core/World/InteriorEntityIdAllocator.cs:48`
  (`0x40000000 | X<<20 | Y<<12 | counter`) to **interior EnvCell-stab
  statics of landblock F418**, counters 0x12–0x15 — NOT landblock objects
  (0xC0000000+ namespace) and NOT scenery (0x80000000+). The slice-5 commit
  message (`0d6cd5c0`) reached the same identification ("EnvCell STAB-LIST
  statics … ids minted by InteriorEntityIdAllocator").
- Retail cell topology at the poses (from the traces, §2.3): `0xF4180104`
  belongs to building `f418000b`'s look-in set; `0xF4180100/0101` to
  `f418000c`'s; `0xF4180106` is punched separately (arrival trace);
  interior floods do not cross between them at the captured camera states.
- The prior campaign's offline sightline probe (recorded in
  `claude-memory/project_pview_visibility_campaign.md` and the PV plan)
  established: the exit portal of the terrace cell and the building's
  never-drawn panel are the SAME surface, and the "#456 seam band" IS the
  terrace cell's portal[4] polygon — i.e. at least one exit aperture is a
  thin band, corroborating slice 6's live finding that scissoring terrain
  to the walk's exit views starves most of the vista of depth/color.

**Unverified (the DAT parse thread had not returned):** the per-cell portal
tables (flags/0x4 exits/other_cell ids) for `0x0104/0x0105/0x0106/0x010D/
0x010F`; WHICH EnvCell's stab list carries counters 0x12–0x15 (the counter
is allocated in ascending cell order in `LandblockBuildFactory`
`src/AcDream.App/Streaming/LandblockBuildFactory.cs:494-503`, so the DAT
stab tables resolve it mechanically); the exit-portal polygon vertex
extents vs the visible opening; whether the lake water is terrain-hosted;
the cathedral shell GfxObj roster (`0x01001FB2/B0/B3` — asserted by the
owner's prior analysis and consistent with the PV panel model
(`0x01001FB0/B2/B3/B7` panels, PV plan §"established model" item 3), but
not independently re-read here).

---

## 4. Divergence table (ranked by causal weight for THIS defect)

| # | Divergence | Ours | Retail | Evidence |
|---|---|---|---|---|
| D1 | **Particle emission site for cell statics/dynamics** | flood-membership + `SphereStraddlesExitPlane` classifier decides pre- vs post-clear emission (slices 4/5) | the owner object's actual walk turn decides: drawn during LS (shadow-cell overlap or look-in) ⇒ landscape scope ⇒ pre-clear drain; drawn in the root flood ⇒ final drain | traces §2.3; model §5; appendix 811; commit msgs `f3a03efc`/`0d6cd5c0` |
| D2 | **Interior "flood" membership for the cell-owners route** | the production cell set treats the connected cathedral complex as interior content (slice-2/3 messages: "the cell-owners route", "the OLD apparatus flood"); walk conformance proves the WALK floods n=1, but consumers were still being cut over one at a time | flood = what survives GetClip from the root; at these poses exactly ONE cell; everything else is landscape-scope | traces §2.3; commit msgs `c40aecfc`/`5f7ccdea`; plan FW3.2b-2 "prepareCells UNIONED" |
| D3 | **Dynamics-last** (register row AD-19, `docs/architecture/retail-divergence-register.md:147`): ALL dynamics in one z-buffered final pass | per-landcell painter-ordered draws inside the landscape pass; interior per cell turn | register row (self-declared); `DrawBlock` 0x005a17c0 / DrawSortCell pc:430124 |
| D4 | **No degrade/LOD admission on this branch** — the marker stalks (Setup `0x0200085A` → GfxObj `0x010001EC`, ladder `0x1100002E` = {self at MaxDist 0, id 0 to ∞}) are DRAWN | retail selects `gfxobj[deg_level]` via `get_degrade` @0x0051E4B0 and **never draws** this model at any distance (gates in `DrawBuilding` @0x0059F2A0 and `CPhysicsPart::Draw` @0x0050D7A0) | `fce250ec` exists ONLY on `claude/cathedral-rendering-debug-47a417` (`git branch -a --contains`; `git merge-base --is-ancestor fce250ec HEAD` = false; `git grep IsNeverDrawnByDegrade -- src` = empty at HEAD) |
| D5 | **Seal/vista coverage geometry**: post-clear alpha can z-pass wherever the visible vista is not covered by a stamped seal; slice 6 proved the walk's exit views at this seam are "thin BANDS far narrower than the real opening" | retail is not exposed to this because the leaking content class isn't post-clear in the first place (D1/D2) | commit msg `bb9212c7`; PV sightline probe (campaign memory) |
| D6 | (regression candidate) straddle-classified emitters now emit pre-clear on interior roots — an interior emitter drained at the landscape flush is subsequently over-painted by the post-clear interior repaint | retail: root-cell emitters drain at the final flush, after interior geometry | mechanism prediction from `f3a03efc`/`0d6cd5c0` + model §5; matches the owner's new "particles WITHIN the cathedral are wrong" report — **unverified until probed** |

The pre-existing #451 fix (owner-accepted 2026-08-27, `docs/ISSUES.md:249-289`)
had already implemented the D1-correct contract for exterior particles
("submits attached and ownerless exterior particles inside `LScape::draw`
for every PView root"). The FW2/FW3 window (`git diff --stat
e102fb36..37febd1f -- src/AcDream.App/Rendering` = ~7,081 insertions:
the whole `Walk/` tree, `WalkFrameDriver`, the static cutover) is the
regression window that displaced it.

---

## 5. Per-commit verdicts

**`37febd1f` (slice 1 — interior outside-view slices from the walk): KEEP.**
Correct single-source-of-truth move (retail has ONE visibility structure);
fixed a real dual-path desync (the #119-family grass flash) with a real
mechanism (old-apparatus fat/degenerate exit views + walk-indexed punch
fans). Not causal for the cathedral defect either way. Its per-view terrain
slice FAN was still non-retail — superseded by slice 6, which it should be
read together with.

**`c40aecfc` (slice 2 — exit seals stamp the walk's flood): KEEP the code,
REJECT the diagnosis (wrong-mechanism).** Stamping the walk's own flood's
exit portals is exactly retail (model §5 seal loop, pc:432785-6, and the
walk flood is conformance-proven against the traces). But the commit's
premise — falls emitters submitting POST-clear is "retail's own timing" —
is refuted by the traces: retail composes those cells pre-clear as
look-ins. Seals could never fix an over-draw whose correct rendering is
"drawn pre-clear with landscape depth"; at best they would z-reject the
falls and make them wrongly INVISIBLE through the aperture. The plan's
slice-2 paragraph (`docs/plans/2026-08-30-campaign-fw-frame-walk.md`
FW4 slice 2) carries the same false premise and should be corrected.

**`5f7ccdea` (slice 3 — outside-stage predicate reads the walk flood):
KEEP.** Feeding predicates from the walk's VisitedCells (root flood +
look-in floods — "all of whose objects retail draws inside LScape::draw,
pre-clear") is the correct retail-shaped direction and removed one more
old-apparatus consumer. Insufficient alone: it gates the DYNAMIC split,
and the falls turned out to be cell statics (slice 5's own finding).

**`f3a03efc` (slice 4 — straddler dynamics' particles pre-clear, once):
WRONG-MECHANISM — revert once D1 lands.** Retail has no exit-plane-straddle
classifier for emission timing; the cited rule ("retail submits an
emitter's polys at its object's FIRST draw — the landscape stage for
anything overlapping outdoor shadow cells") is right, but the
implementation substitutes a plane-straddle test for draw-site membership.
It under-covers emitters wholly OUTSIDE the exit plane (they never
"straddle" ⇒ stay post-clear ⇒ still leak) and over-covers interior
straddlers into the pre-clear drain where the interior repaint erases them
(divergence D6 — the likely source of the new in-cathedral particle
wrongness). Drawn-once bookkeeping (each owner emits exactly once) is worth
preserving in whatever replaces it.

**`0d6cd5c0` (slice 5 — straddling cell-statics' particles pre-clear):
WRONG-MECHANISM — revert once D1 lands.** Its identification work is the
best of the six (falls = EnvCell stab statics; the shadow-cell rule
correctly cited at `DrawBlock` pc:430056-430064), but it ports the rule as
the same geometric straddle test instead of the actual membership question
("is this object drawn during the landscape scope this frame?" — for the
falls cells at these poses: yes, as building look-ins, regardless of any
plane test). Same under/over-coverage failure modes as slice 4.

**`bb9212c7` (slice 6 — interior roots draw landscape unclipped): KEEP.**
Matches retail exactly: landscape content is view-CULLED, never
view-CLIPPED (model §3: the views feed only `draw_check_blocks`' in_view
union; `set_view` installs no GPU state; no scissor exists). Its probe
finding — falls submitted pre-clear with depth LESS still passed because
the scissored terrain had left the vista without depth — is the
load-bearing discovery of the round and independently confirms the thin-band
aperture geometry. It cannot, by itself, fix emitters that still submit
post-clear on other frames/poses, and it does not address D6.

---

## 6. Why the symptom survived all six fixes

1. **A wrong premise was locked in at slice 2 and never re-examined against
   the traces the campaign itself captured.** "The falls submit post-clear —
   retail's own timing" is contradicted by `posed/terrace-center.log` /
   `posed/cathedral-arrival.log`: retail's interior flood at these poses is
   ONE cell and the falls' owner cells are landscape-scope look-ins. Every
   subsequent fix (seals, predicates, straddle emission) tried to make a
   post-clear world safe instead of putting the content in the pre-clear
   world where retail has it.
2. **The corrective classifier is not retail's rule.** The straddle test
   (slices 4/5) approximates "overlaps outdoor shadow cells" with "sphere
   crosses the exit plane" — a strictly narrower predicate that misses
   fully-outside emitters (the falls hang OVER the lake) and wrongly
   captures interior straddlers.
3. **Mixed visibility sources during the staged cutover.** Slices 2 and 3
   each discovered another consumer still reading the OLD apparatus's flood
   (seal set, outside-stage predicate). The FW3.2b-2 design explicitly runs
   old visibility for dynamics beside the walk for statics
   (`docs/plans/2026-08-30-campaign-fw-frame-walk.md`); every such seam is
   a place where the walk's correct n=1 flood is not what production
   consumes. AD-19 (dynamics-last) keeps the weenie stalks post-clear
   regardless.
4. **Two of the leaking content classes cannot be fixed by ANY
   ordering/seal work:** the marker stalks should never be drawn at all
   (D4 — the degrade admission port is quarantined off-branch), and
   pre-slice-6 the vista had no depth to occlude against (D5) — so even
   correct pre-clear emission "passed" its z-test into stale color.
5. **Each fix was validated against the previous fix's failure, not against
   a falsifiable retail prediction.** The probes pinned real facts
   (phase=pre/post, straddler classification) but the acceptance question
   was "did the leak stop" rather than "does the frame now match §2.1's
   shape at this pose" — so five plausible partial mechanisms shipped in
   one day without any landing the frame-shape divergence (D1/D2).

---

## 7. Recommended fix plan (mechanism-first)

**Step 0 — probes before code (falsifiable predictions):**

- **P1:** With `ACDREAM_PROBE_WALK_ROOT` at the terrace pose on HEAD, the
  falls owners `0x4F418012-15` will log submission OUTSIDE the landscape
  scope (post-clear route or final drain) on defect frames, while the
  walk's own event stream visits their owner cells at BUILDING LOOK-IN
  turns (not in the interior flood, which stays n=1). If instead they
  already log landscape-scope submission + pre-clear drain on defect
  frames, D1 is falsified — investigate the drain's depth state
  (attachment, compare op) instead.
- **P2:** The DAT stab tables will place stabs #0x12-0x15 in cell(s) OTHER
  than the frame's root cell at the defect poses (look-in-reached cells).
  If they are stabs of the root cell itself, the look-in theory is
  falsified.
- **P3:** Forcing the falls emitters to submit at their owner cell's
  look-in turn (landscape scope, drained at the pre-clear boundary flush)
  removes the over-draw at EVERY camera on interior roots, while the falls
  stay visible through the opening and terrain-occluded exactly as on
  outdoor roots.
- **P4:** Reverting slices 4/5's straddle emission (in favor of the
  walk-turn rule) makes the new "particles within the cathedral are wrong"
  report disappear (root-cell emitters return to the final drain).
- **P5 (optional, owner-assisted):** a cdb capture at the terrace with a
  breakpoint on the particle-poly alpha-list insertion will show falls
  polys entering the list BEFORE `DrawCells`' depth clear on
  interior-rooted retail frames.

**Step 1 — the emission-site port (fixes the falls).** An object's
particles submit when and where the object itself draws in the walk:
look-in cell content and outdoor shadow-cell content submit during the
landscape turn and drain at the pre-clear boundary flush; root-flood cell
content submits at its cell turn and drains at the final flush. Retail
pins: appendix 811 (look-in `DrawCells` inside the landscape scope),
`DrawBlock` pc:430056-430064 (shadow-cell object draw), model §5 (the two
drain sites). Delete `SphereStraddlesExitPlane`-based emission (slices
4/5) in the same commit; keep the emit-once ledger.

**Step 2 — finish the flood-consumer cutover (fixes the class).** Every
remaining consumer of the old apparatus's cell set (cell-statics particle
owners, dynamics routes, prepare unions) reads the walk's per-turn visited
sets. AD-19's interior-root half retires when dynamics draw at their
cell's walk turn; if that is deferred, dynamics must at minimum gate on
the walk's visited set so a non-visited cell's weenies cannot draw at all.

**Step 3 — re-land the marker-degrade admission (fixes the stalks being
visible at all).** `fce250ec`'s mechanism (never-drawn degrade ladders:
`get_degrade` @0x0051E4B0; `gfxobj[deg_level] != 0` gates) is a retail
port stranded on the quarantined branch. Re-land it cleanly on this branch
(fresh commit, not a cross-merge from quarantine), covering static AND
dynamic classifiers. If stalk-like shapes remain afterwards, identify by
guid before theorizing (they'd be weenies with a different model —
campaign-memory rule).

**Step 4 — verification gates.** The ten oracle fixtures stay green (the
walk itself is already conformant); add a fixture-level assertion that the
DRIVER's submission stream places look-in-cell content in the landscape
scope (the current conformance compares walk events, not submission
scope — that gap is how D1 shipped); then the owner matrix: terrace both
cells, seam crossing, outdoor falls, interior candles, doorway flap,
Holtburg exit.

---

## 8. Open questions

- **Q1:** Why are the walk's exit views at this seam thin bands — is the
  full visible opening authored as multiple portals (0/1/2/4) of which
  only portal 4 survives GetClip at these camera states, or is our
  clip/winding at fault, or does the chase camera sit outside the cell
  volume? (Slice 6 measured the symptom; the cause is unestablished. The
  PV probe's "panel ∪ solid covers every sightline" was measured at ≤6 m
  camera rises only.)
- **Q2:** Which EnvCell(s) own falls stabs #0x12-0x15, and do the falls
  additionally exist as dynamics (slice 3 probed entities "f4243/f4285"
  as [walk-dyn] — the relationship between those ids and the stab owners
  is unestablished). **DAT parse owed.**
- **Q3:** The exact HEAD drain/depth state of `ParticleRenderer` under
  Vulkan (depth attachment, compare op, write mask) at each drain site —
  required to close P1's alternative branch. **Code audit owed.**
- **Q4:** Whether `ShouldDrawParticles` (@0x0050FE60) is evaluated
  per-frame or per-view in our port, and against which cell set at HEAD.
- **Q5:** The gated clear's `portalsDrawnCount` semantics across frames
  (seals increment it AFTER the clear check — does the first interior
  frame after an outdoor frame skip the clear in retail?), and whether our
  `slices>0` production gate is equivalent.
- **Q6:** Whether the seal fans at HEAD still apply the old assembly's
  per-cell slice clips ("where present", slice 2) and whether that can
  shrink a seal below its authored polygon.
- **Q7:** The uncharacterized in-cathedral particle wrongness (owner
  report #3) — D6 is a prediction, not a diagnosis; one probe frame with
  `[walk-part]`/`[walk-alpha]` at a candle would settle it.

---

*Reviewer: Fable. All decomp addresses cite the named 2013 build
(`docs/research/named-retail/`); trace lines cite files under
`docs/research/2026-08-30-fw-walk-oracle/posed/`; commit claims cite the
SHAs in §5; everything not directly read is marked unverified above.*