🔀 u-blade / n-blade Slot System - Blade Generation System

🆕 Added February 2, 2026 — Blade Slot Orientation Nomenclature

Standardized naming for how blades slot into their parent (baseplate or cross-blade). Uses lowercase u and n based on the visual profile of the slot opening. Think of a wine box divider: the cardboard pieces have slots cut from alternating directions so they interlock.

📐 Slot Type Definitions

u-blade: Slot cut from TOP n-blade: Slot cut from BOTTOM (Blade stands in a U-shaped channel) (Blade hangs from an inverted-U) ┌─────────┐ ┌───┐ ┌───┐ │ │ │ │ │ │ │ BLADE │ │ BLADE │ │ BODY │ │ BODY │ │ │ │ │ ┌────┘ └────┐ │ │ │ │ └────┬────┘ │ BASE PLATE │ │ └───────────────────┘ ─────┴───── BASE PLATE Slot opens UPWARD Slot opens DOWNWARD Blade sits IN the slot Blade straddles OVER from above from below Mixed u+n blade (cross-blade with slots from both directions): ┌───┐ ┌───┐ │ │ │ │ ← n-slot (receives cross-blade from below) │ │ │ │ ┌────┘ │ │ └────┐ │ │ │ │ │ BLADE │ │ BODY │ │ │ │ │ ┌────┘ └───┘ └────┐ │ │ │ BASE PLATE │ ← u-slot (sits in baseplate) └───────────────────────────────┘

🔴 Programmable Reference Dot (Red Dot) Position

The red dot marks the reference face on a blade for assembly orientation. Its position must survive the slot cut — if the dot is placed in the zone that gets removed by the slot, it disappears.

RED DOT PLACEMENT LOGIC u-blade (slot from top): n-blade (slot from bottom): ┌─────────┐ ┌─────────┐ │ ╳ SLOT │ ← removed zone │ │ │ ╳ ZONE │ │ ● DOT │ ← safe: ABOVE slot │─────────│ │ (TOP) │ │ │ │─────────│ │ ● DOT │ ← safe: BELOW slot │ ╳ SLOT │ ← removed zone │ (BASE) │ │ ╳ ZONE │ └─────────┘ └─────────┘ Mixed u+n blade: ┌─────────┐ │ ╳ n-SL │ ← removed (top) │─────────│ │ ● DOT │ ← safe zone: BETWEEN both slots │─────────│ │ ╳ u-SL │ ← removed (bottom) └─────────┘ Algorithm: 1. Determine slot_type (u, n, or mixed) 2. u-blade → fxFindFaceByPosition LOWEST → place dot 3. n-blade → fxFindFaceByPosition HIGHEST → place dot 4. Mixed → find face between upper and lower slot boundaries

✓ fxFindFaceByPosition.ovm — supports HIGHEST/LOWEST face finding
○ Decision logic: map slot_type → dot placement strategy
○ Mixed u+n safe-zone calculation (between both slot boundaries)
○ Integration with blade build pipeline (dot placed after profile, before edge mods)
○ Dot survives SLD boolean operations (verify not consumed by slot cut)

📋 JSON Schema: `slotType` Field

Added to blade_params.schema.json v1.2. Three values with hierarchical override:

Value	Meaning	Red Dot Strategy
`"u"`	Slot from top — blade sits in a U-channel	Place near BASE (lowest face)
`"n"`	Slot from bottom — blade straddles over	Place near TOP (highest face)
`"auto"`	Resolve from geometry after build	Auto-detect, then replace with resolved value

⚠️ Override Hierarchy

Zone-level default → Blade-level override → auto-resolve from geometry. After build completes, any "auto" values are replaced with the resolved "u" or "n" so the JSON becomes a reproducible build record.

📦 Schema Change

blade_params.schema.json — added slotType field (enum: u, n, auto)

blade_params_example.json — added "slotType": "auto"

📝 Naming Rationale

Why u/n? The letters visually represent the slot shape. A u is a channel open at the top; an n is a channel open at the bottom. Alternative names were considered and rejected:

male/female — too ambiguous when a blade has multiple slots in different directions
androgynous — overcomplicated for a mixed u+n blade
top/bottom — confusing when blades are at compound angles

The wine box divider analogy makes the concept immediately intuitive for shop floor communication.

🔀 u-blade / n-blade Slot Type System