position and dimensions are in INCHES (SketchUp's internal unit).
For a cylinder, position is the corner of its bounding box (not the
centre) and dimensions are [diameter, ignored, height].
A cube placed at z=0 extrudes DOWNWARD (z from -height to 0).
For real modelling work prefer eval_ruby.

Supported names: red, green, blue, yellow, cyan, magenta, white, black,
brown, orange, gray. For any other colour use eval_ruby with
Sketchup::Color.new(r, g, b).

The file is written to the sketchup_exports folder inside %TEMP% and its full path is
returned in content[0].text. Use format='png' to get a screenshot of the
current view so you can check the model visually.

All numbers are METRES. Coordinates are [x, y] on the ground plane.
spec = {
  "building": "Rumah A",         # container group for the whole building
  "name": "Lantai 1",            # name of this floor's group
  "wall_height": 3.0,            # default height
  "wall_thickness": 0.15,        # default thickness
  "base_z": 0,                   # floor level (use 3.2 etc. for upper floors)
  "wall_ref": "center",          # default for "ref" below
  "walls": [                     # from/to line of each wall, see "ref"
    {"id": "W1", "from": [0, 0], "to": [6, 0]},
    {"id": "W2", "from": [6, 0], "to": [6, 4], "thickness": 0.1, "height": 2.8}
  ],
  "openings": [                  # offset = distance from the wall's "from"
    {"wall": "W1", "type": "door",   "offset": 1.0, "width": 0.9, "height": 2.1},
    {"wall": "W2", "type": "window", "offset": 1.2, "width": 1.5, "sill": 0.9, "height": 1.2}
  ],
  "slab": {"outline": [[0, 0], [6, 0], [6, 4], [0, 4]], "thickness": 0.12}
}
An opening with no "sill" (or sill 0) is a door; with a sill it is a window.
Doors get a 4 cm leaf and windows a 1 cm glass pane ("infill": false for
plain holes). Walls and slab accept "material": "Dinding - Bata Ekspos".
"ref" on a wall says what its from/to line is: "center" (centreline,
the default), "left" or "right" (that face of the wall, as seen walking
from `from` to `to`; the wall body lies on the other side). Use the one
the plan is dimensioned to, or the error equals the wall thickness:
- outside dimensions of the building: trace the outline anticlockwise
  with "ref": "right";
- clear (inside) dimensions of a room: trace the room anticlockwise
  with "ref": "left";
- grid/axis dimensions: "center".
Where walls meet, their ends are lengthened or trimmed automatically so
corners close and walls do not overlap ("extend": false, a number, or
[start, end] in metres overrides that for one wall).
The whole plan is one undo step. The reply reports the built size and any
opening that was skipped (for example because it does not fit the wall):
read it, then call verify_dimensions and look at export_scene(format="png").

chains = [
  {"label": "Sisi depan", "segments": [1.0, 0.9, 0.5, 1.5, 2.1], "total": 6.0},
  {"label": "Sisi kiri",  "segments": [3.0, 3.0], "total": 6.0}
]
All numbers in metres. For every chain the segments are summed and compared
with the overall dimension. Does not need SketchUp. If any chain is in
conflict, show the user which one and ask which number wins; do not guess.

checks (metres) can mix three kinds:
  {"label": "Panjang luar", "overall": "x", "expected": 6.0}
      outside size of all walls along x or y; optional "building" and
      "floor" (group names) limit which walls are counted
  {"label": "Kamar tidur 1", "at": [1.5, 4.5], "expected": [2.8, 2.8]}
      clear room size through that point: [along x, along y]
  {"label": "Lebar koridor", "at": [3, 2], "axis": "y", "expected": 1.2}
      one clear distance; axis is "x", "y" or an angle in degrees
"at" is any point inside the room, away from the walls. Clear distances
are measured between wall faces (doors, glass and furniture are ignored;
openings do not fool it). Add "z" (floor level) for upper floors. Leave
"expected" out to just read a dimension.
Every line is OK or SELISIH with the difference in mm. Run this after
build_floor_plan with the key dimensions from the plan, fix what differs,
and pass the report on to the user.

This is the main modelling tool. Rules that avoid the usual mistakes:
- Lengths are inches internally. Write 3.m, 150.mm, 15.cm, never bare numbers.
- model = Sketchup.active_model; wrap edits in
  model.start_operation('name', true) ... model.commit_operation.
- A face on the ground plane (z=0) has its normal pointing down, so
  pushpull(+h) would go underground: face.reverse! if face.normal.z < 0.
- Create each element with SU_MCP.element(name, kind, parent) { |ents| ... }
  so it gets the standard tag and material; parent = SU_MCP.container('Rumah A').
- End with SU_MCP.audit_model; the work is done only when it says AUDIT OK.
- Make the last expression a short summary string (counts, bounds) so you
  can verify the result. Calls time out after about 15 seconds, so split
  very large jobs into several calls.