Charter open mystery #1 (docs/research/2026-06-11-building-render-holistic-
port-handoff.md "4.1): the e46d3d9 DrawingBSP poly filter made doors vanish
because the PosNode/NegNode walk only collected node.Polygons and never
node.Portals (List<PortalRef> {PolyId, PortalIndex}).
Dat-proven across all 13 Holtburg-area building models (A9B4/A9B3/AAB3/
A9B5/AAB4): TRUE-orphans = ZERO everywhere. Every dictionary poly the
filter dropped is a PORTAL POLYGON - the baked door-filling (1.9x2.5 m)
and window-filling quads at doorway/window apertures, AND the meeting
hall's phantom stair polys {0,1} (ramp-shaped portal apertures into the
interior stair cells).
Consequences for the holistic port:
- The door entities (setup 0x020019FF) were never affected: base parts +
every degrade variant have full BSP coverage, and doors don't take the
IsIssue47HumanoidSetup degrade swap. The vanished 'doors' were shell
portal polys.
- Retail draws portal polys CONDITIONALLY during portal-view traversal
(closed doors/windows draw a surface; open apertures and the hall's
stair apertures don't). The phantom staircase and the door rendering
are the SAME mechanism with opposite signs - there is NO correct
static filter; this is the dat-side proof the one-drawing-discipline
port is required.
- The exact retail conditional (BSP portal-node draw gate in
CPhysicsPart::Draw / BSPPORTAL) is a named Phase A question.
Diagnostic-only commit: new dump facts in
Issue113DoorVanishDiagnosticTests (door setup + degrade chains, control
models, Holtburg orphan sweep with portal discrimination). No production
code.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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