DIN 18015-3 Installation Zone Visualization

Purpose

Computes and visualizes cable installation zones on wall and ceiling surfaces according to German electrical norms (DIN 18015-3). Shows where cables can go (green), where they normally run (blue), and where they're forbidden (red).

Normative Source

Based on Kabelverlegung in Wohnungen und Büros.md which contains machine-readable parameters derived from DIN 18015-3 and DIN VDE 0100-520.

Files

Zone Measurements

Horizontal Zones (along wall length)

Vertical Zones (floor to ceiling)

Absolute Forbidden Areas (Dark Red)

These are structural exclusion zones — never place cables here.

Vertical Transit Zone (Yellow)

The "dead zone" between horizontal zones. Cables cannot run horizontally here, but a vertical Stichleitung (perpendicular feed line) is allowed to connect a device to the nearest horizontal zone above or below.

Cable Depth Constraints

Computed per-wall by _get_max_depth_mm(thickness_m, is_load_bearing) using wall thickness from IFC geometry and LoadBearing from Pset_WallCommon.

By Wall Thickness (automated):

By Material (reference, not yet auto-detected):

Each green zone carries its wall-specific depth_mm value in the JSON output.

Calculation Steps

Step 1: Wall Analysis

For each wall: 1. Compute thin_axis (thickness direction) via np.argmin(wall_size[:2]) 2. Two faces: face_a = bbox_min[thin_axis], face_b = bbox_max[thin_axis] 3. Wall surface is a rectangle: u_min→u_max (along long axis) × v_min→v_max (floor to ceiling) 4. Extract LoadBearing from Pset_WallCommon via _get_wall_properties() 5. Compute depth_mm from wall thickness via _get_max_depth_mm() — stored on every green zone

Step 2: Junction Detection (_detect_junctions)

Finds ALL points where other walls meet this wall:

• End junctions: where this wall's end meets a perpendicular wall → type "end"
• T-junctions: where a perpendicular wall meets this wall mid-span → type "t_junction", generates two junction points (at both edges of the intersecting wall's thickness)
• Parallel junctions: end-to-end connections → type "end"

T-junctions are critical: they split the wall into segments, each getting its own set of ZS-e corner zones and independent horizontal zones.

Step 3: Exterior Face Detection (_is_face_interior)

For each wall face, checks if a room (IfcSpace) is adjacent:

• Gets space bounding boxes
• For min-face: checks if any space has bbox_max[thin_axis] ≈ face_coord
• For max-face: checks if any space has bbox_min[thin_axis] ≈ face_coord
• Exterior faces get no zones (no cables on building exterior)
• Interior faces get full zone computation

Step 4: Zone Generation (_compute_face_zones)

For each interior face:

1. Collect split points from T-junctions
2. Generate horizontal zones for each segment between split points:
3. ZW-o (upper green), ZW-u (lower green)
4. Segments interrupted at T-junctions
5. Generate door zones (ZS-t):
6. Green vertical strip on each side of door frame (10-30cm from edge)
7. Red forbidden strip (0-10cm from edge)
8. Red door opening rectangle
9. Generate corner zones (ZS-e):
10. At wall ends: green strip going inward
11. At T-junctions: green strips on BOTH sides + red forbidden strip at junction
12. Generate forbidden zones (dark red):
13. Ceiling/floor red strips (0-15cm)
14. Door/corner exclusion (0-10cm from edges)
15. Door opening rectangles
16. Generate dead zones (yellow):
17. Segments between vertical zones in the mid-wall area (between ZW-u top and ZW-o bottom)
18. Vertical Stichleitung allowed here, horizontal cables forbidden
19. Generate blue preferred paths:
20. Thin 2cm strips at zone centers (30cm from ceiling/floor, 15cm from edges)

Step 5: Mode Variants

Query parameter ?mode=normal|false_ceiling|false_floor:

Step 6: Ceiling Zone Computation (tools/_ceiling_zones.py)

Ceiling zones are computed per IfcSpace (per room), not per slab. A single IfcSlab spans the entire storey; walls divide the space below into rooms.

• Ceiling Z: space.bbox_max[2] (top of room = ceiling surface from below)
• Slab thickness: found by matching slab whose bbox_min[2] is near space.bbox_max[2] (metadata only)
• Room footprint: space.bbox_min/max in X/Y defines the ceiling rectangle

Solid Ceiling Zones (normal mode)

Door-space association: doors are matched to spaces by geometric proximity to space faces.

False Ceiling Zones (false_ceiling mode)

Single green rectangle per room, 10cm below ceiling surface, covering the full room footprint. Includes metadata flags: - strain_relief_required: true - max_tension_install_n_mm2: 50 (during cable installation) - max_tension_permanent_n_mm2: 15 (permanent load, requires cable trays)

Step 7: Caching

Saved as uploads/<stem>.wall_zones_<mode>.json. Loaded from cache on subsequent requests.

JSON Output Structure

{
  "walls": [{
    "wall_id": 291,
    "wall_name": "Basiswand:STB 200:2521964",
    "thickness_m": 0.2,
    "is_load_bearing": false,
    "max_depth_mm": 30,
    "faces": [{
      "face_coord": 5.1,
      "thin_axis": 1,
      "long_axis": 0,
      "u_range": [0.3, 6.3],
      "v_range": [0.0, 2.8],
      "is_interior": true,
      "zones": [
        {"type": "ZW_o", "category": "green", "depth_mm": 30,
         "corners": [[0.3, 5.1, 2.35], [6.3, 5.1, 2.35], [6.3, 5.1, 2.65], [0.3, 5.1, 2.65]]},
        {"type": "forbidden_ceiling", "category": "red",
         "corners": [[0.3, 5.1, 2.65], [6.3, 5.1, 2.65], [6.3, 5.1, 2.8], [0.3, 5.1, 2.8]]},
        {"type": "ZW_o_center", "category": "blue",
         "corners": [[0.3, 5.1, 2.49], [6.3, 5.1, 2.49], [6.3, 5.1, 2.51], [0.3, 5.1, 2.51]]}
      ]
    }]
  }],
  "ceilings": [{
    "space_id": 46,
    "space_name": "Raum 1",
    "ceiling_z": 2.4384,
    "slab_thickness_m": 0.2,
    "zones": [
      {"type": "ZD_r", "category": "green",
       "corners": [[0.5, 5.5, 2.44], [6.1, 5.5, 2.44], [6.1, 5.8, 2.44], [0.5, 5.8, 2.44]]},
      {"type": "ZD_false_ceiling", "category": "green",
       "strain_relief_required": true,
       "max_tension_install_n_mm2": 50,
       "max_tension_permanent_n_mm2": 15,
       "corners": [[0.3, 5.3, 2.34], [6.3, 5.3, 2.34], [6.3, 10.1, 2.34], [0.3, 10.1, 2.34]]}
    ]
  }],
  "mode": "normal",
  "stats": {"wall_count": 5, "zone_count": 207, "ceiling_count": 2, "ceiling_zone_count": 28}
}

Viewer Visualization

• Checkboxes: "Wall Zones", "Ceiling Zones" (independent toggles)
• Mode options: "Abgehängte Decke" (false ceiling), "Doppelter Boden" (raised floor)
• Storey-aware: zones filtered by active storey selection

Color Scheme

Rendering Details

• Batched rendering: all zone quads of the same color category are merged into a single THREE.BufferGeometry (~8 total meshes instead of one per zone). This reduces 50,000+ individual objects to ~8 for large models.
• THREE.MeshBasicMaterial (flat, unlit) with depthTest: false, depthWrite: false
• Zone groups use renderOrder: 1 so they always render on top of wall geometry
• Zone data cached in JS (zoneDataCache); storey filter rebuilds merged geometry from cache