Technical Drawing

┌─────────────────────────────────────────────────┐
│ [20mm]        DRAWING AREA              [10mm]  │
│       ┌─────────────────────────────┐           │
│[10mm] │                             │ [10mm]    │
│       │   TECHNICAL DRAWING         │           │
│       │   (scale 1.30 recommended)  │           │
│       │                             │           │
│       │   SCALE BAR    NORTH        │           │
│       │   NOTES                     │           │
│       ├─────────────────────────────┤           │
│       │ TITLE BLOCK (ISO 7200)      │           │
│[10mm] └─────────────────────────────┘           │
└─────────────────────────────────────────────────┘

Design System

Page

body {
  background: #0f1117;           /* dark surround */
  font-family: 'Inter', system-ui, sans-serif;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.drawing-board {
  max-width: 1340px;
  aspect-ratio: 420 / 297;       /* A3 landscape */
  background: /* grid + white */
    linear-gradient(rgba(160,175,200,0.10) 1px, transparent 1px),
    linear-gradient(90deg, rgba(160,175,200,0.10) 1px, transparent 1px),
    linear-gradient(rgba(160,175,200,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(160,175,200,0.04) 1px, transparent 1px),
    #ffffff;
  background-size: 72px 72px, 72px 72px, 14.4px 14.4px, 14.4px 14.4px;
  border-radius: 3px;
  box-shadow: 0 4px 60px rgba(0,0,0,0.5);
}

Colors

Line Weights (ISO 128)

Line Types

Continuous ─────────   Visible edges, walls
Dashed - - - - -       Hidden elements, reference lines (stroke-dasharray="2,3")
Dot-dash —·—·—         Axes, partition walls (stroke-dasharray="8,3,2,3")

Dimension System (Cotas)

Indicators

• Primary cotas: Architectural tick (diagonal 45°, red #c0392b)
• Secondary cotas: Smaller tick or filled arrow
• All text on white background (<rect> behind <text> for legibility)

Tick Markers (SVG defs)

<!-- Primary tick -->
<marker id="tick" markerWidth="8" markerHeight="8" refX="4" refY="4" orient="auto">
  <line x1="0" y1="8" x2="8" y2="0" stroke="#c0392b" stroke-width="1.2"/>
</marker>

<!-- Secondary tick -->
<marker id="tick2" markerWidth="6" markerHeight="6" refX="3" refY="3" orient="auto">
  <line x1="0" y1="6" x2="6" y2="0" stroke="#c0392b" stroke-width="0.9"/>
</marker>

<!-- Filled arrows for small cotas -->
<marker id="al" markerWidth="6" markerHeight="6" refX="6" refY="3" orient="auto">
  <path d="M6,0 L0,3 L6,6" fill="#c0392b" stroke="none"/>
</marker>

Horizontal Cotas (3 levels below drawing)

L1 (closest): Individual openings — red, tick2 markers
L2 (middle):  Zone parciales — navy, tick markers
L3 (farthest): Total exterior — navy, tick markers, bold text

Vertical Cotas — Use Level Marks

Instead of stacked dimension lines, use level marks (marcas de nivel):

<!-- Level mark: triangle + boxed value -->
<g transform="translate(-82, {y_position})">
  <polygon points="0,0 6,-4 6,4" fill="#1a2744"/>
  <rect x="7" y="-6" width="28" height="12" fill="#ffffff" rx="1" stroke="#1a2744" stroke-width="0.3"/>
  <text x="21" y="3" text-anchor="middle" font-size="8" fill="#1a2744" font-weight="700">+0.00</text>
</g>

Level marks are cleaner than stacked dimension lines. Use red (#c0392b) for opening levels, navy for structural levels.

Text Behind White Background

Every dimension text MUST have a white rect behind it:

<rect x="{text_x - 14}" y="{text_y - 8}" width="28" height="10" fill="#ffffff" rx="1"/>
<text x="{text_x}" y="{text_y}" text-anchor="middle" font-size="9" fill="#c0392b" font-weight="600">1.80</text>

Title Block (ISO 7200)

Position: bottom-right corner of frame. 510u × 165u.

Naming Convention

{PROJECT}-{DISCIPLINE}-{NUMBER}

ET-ARQ-001    EterHabitats, Arquitectura, Planta
ET-ARQ-002    EterHabitats, Arquitectura, Elevación
ET-EST-001    EterHabitats, Estructura, Detalle

Scale Bar

Always include. Alternating black/white segments, 5m total at 1:50.

<g transform="translate(x, y)">
  <text x="0" y="-6" font-size="7" fill="#1a2744" opacity="0.5">ESCALA 1:50</text>
  <!-- 1m = 60u at 1:50 -->
  <rect x="0" y="0" width="60" height="4" fill="#1a2744"/>
  <rect x="60" y="0" width="60" height="4" fill="none" stroke="#1a2744" stroke-width="0.4"/>
  <!-- ... repeat ... -->
  <text x="0" y="12" text-anchor="middle" font-size="5.5" fill="#1a2744">0</text>
  <text x="300" y="12" text-anchor="middle" font-size="5.5" fill="#1a2744">5m</text>
</g>

SVG Coordinate System

viewBox: "0 0 1260 891" (A3 proportions × 3 for resolution)
1 SVG unit ≈ 0.333mm paper

Frame: x=60 y=30 → x=1230 y=861 (margins: 20mm left, 10mm others)
Title block: translate(720, 696)

Drawing group: translate + scale(1.30) for comfortable viewing
Scale factor at 1:50: 1m real = 60 SVG units

Print Support

@media print {
  body { background: white; padding: 0; }
  .drawing-board {
    box-shadow: none; border-radius: 0;
    max-width: none; width: 420mm; height: 297mm;
  }
  @page { size: A3 landscape; margin: 0; }
}

Implementation Steps

1. Read project specs (dimensions, materials, openings)
2. Calculate SVG coordinates: dimension_m × 60 = SVG units
3. Build SVG with frame → title block → drawing group → cotas → scale bar → notes
4. Apply scale(1.30) to drawing group for comfortable size
5. Write to {project}/docs/planos/{name}.html
6. Open with open {path}

Conventions

• All measurements in meters (display without "m" suffix in cotas, with suffix in notes)
• Openings identified as V-01 (ventana), D-01 (puerta), P-01 (portón)
• Zones labeled in uppercase, low opacity, inside the drawing
• North arrow always present
• Notes section below drawing, numbered list
• Spanish neutral LATAM for all text

Reference Implementation

• Floor plan: projects/eterhabitats/docs/planos/container-planta.html
• Elevation: projects/eterhabitats/docs/planos/container-elevacion.html

Anti-patterns

• NO rotated text on vertical dimensions — use level marks instead
• NO overlapping dimension lines — separate into clear levels
• NO dimension text without white background
• NO colored fills on structural elements — navy lines on white only
• NO multiple accent colors — navy for structure, red for opening cotas only
• NO AI-slop gradients or decorative elements