merge des aktuelllen Standes

doc/Python_Scripts.md

@@ -162,12 +162,42 @@ id ranges, e.g. `Gefaellestrecke 0017 - 0036 (20x)` / `Separator (20): 0037 -
 in `lib/material_flow.py`) — the underlying graph, `--doc` report and
 `--connect` output are unaffected and still list every line individually.
 
-Flow direction between conveyor segments is derived from height change
-(`Hoehe_Von_mm`/`Hoehe_Bis_mm`) or, failing that, from `Antriebfahrtrichtung`
-("Auf"/"Ab"); connections whose direction can't be determined are drawn
-bidirectional and reported as a warning. `--doc` additionally cross-checks
-stated `Anzahl_Separator`/`Anzahl_Scanner` counts against what was actually
-attached.
+Flow direction between a Kreisel and a Strecke/Gefällestrecke is set from the
+**Ausschleus-/Einschleuselement** at each end (`_apply_transfers`): the
+Ausschleuselement is the Kreisel outlet (Kreisel → Strecke, start), the
+Einschleuselement the inlet (Strecke → Kreisel, end). A conveyor whose two ends
+dock on the *same* Kreisel (a return line — Eingang and Ausgang on one Kreisel)
+is drawn as **two** edges — one onto each lane (`0006-L → VF` on the way out,
+`VF → 0006-R` on the way back) — so it is never flat/undetermined. The transfer
+element names its conveyor via the `Strecke` **or** `Foerderer`/`Förderer`
+attribute (both are read).
+
+Where no transfer element resolves the direction, `drive_uphill` applies the
+physics rule: **only a pure Gefällestrecke** takes its direction from the height
+(`Hoehe_Von_mm`/`Hoehe_Bis_mm` → flows downhill; a GF with no height runs downhill
+by definition). A Förderer (VF) can convey up *or* down and a `Strecke` is often
+a mixed GF/VF chain, so **height is not a direction indicator for them** — they
+use an unambiguous `Antriebfahrtrichtung` (exactly `"Auf"`/`"Ab"`, not a mixed
+list like `"horizontal,horizontal,Auf"`) and otherwise stay undetermined
+(direction is expected to come from the AS/ES ends). Only what nothing resolves
+is drawn bidirectional and reported as a warning.
+
+Entry/exit stations are hung on the Kreisel **lane** they belong to
+(`_attach_stations`): first the Kreisel whose `TrackIds` umlauf lists the station,
+then the entry-/exit-lane from its `Drehrichtung` (UZS → entry lane R / exit lane
+L, GUZ reversed). Sources (`Beladung`/`Eingang`) get `Station → lane`, sinks
+(`Entladung`/`Ausgang`) `lane → Station`. Neighbours that aren't flow objects
+(another station, a separator) are skipped, so two BTMT points no longer get
+wired to each other.
+
+`Eingang`/`Ausgang` are the **generic symbols** for the concrete BTMT stations
+`Beladung`/`Entladung` (same source/sink role). When a symbol lies almost on top
+of a BTMT station of the same role (≤ `STATION_MERGE_MM` = 600 mm, `x`/`y` from
+the `Position` column), only **one** node is drawn: the concrete BTMT station is
+kept, the generic symbol is swallowed (`_merge_station_symbols`). A standalone
+`Eingang`/`Ausgang` with no nearby BTMT partner is drawn as its own green/red
+node. `--doc` additionally cross-checks stated `Anzahl_Separator`/`Anzahl_Scanner`
+counts against what was actually attached.
 
 `--track` builds a second, finer-grained graph in addition to the one above:
 Separator, Ausschleus-/Einschleuselement, Weiche and the entry/exit points