3. Creating Buildings

This chapter covers all aspects of creating buildings in CitySketch, from basic rectangular structures to advanced rotated buildings with precise dimensions.

3.1. Building Creation Modes

CitySketch offers two primary building creation modes, each optimized for different building types:

3.1.1. Block Building Mode

Activation: Click “Add Block Building” button or use keyboard shortcut

Best For: - Rectangular buildings - Buildings aligned with streets or property lines - Structures requiring precise corner placement - Buildings that need rotation after creation

Creation Process: 1. First click sets the anchor corner (lower left corner) 2. Mouse movement (up / right) shows building preview 3. Second click completes the building

3.1.2. Round Building Mode

Activation: Click “Add Round Building” button

Best For: - Circular or round buildings - Towers, silos, and cylindrical structures - Buildings where radius is the primary dimension - Quick creation of symmetrical structures

Creation Process: 1. First click sets the center point 2. Mouse movement shows circular preview 3. Second click sets the radius and completes the building

3.1.3. Using Snap-to-Grid

Enable Snapping: Toggle the “Snap: ON/OFF” button in toolbar

Snap Targets: - Corners of existing buildings .. - Edges of existing buildings .. - Grid intersections (when no basemap is active)

Snap Threshold: Approximately 15 pixels at current zoom level

3.2. Advanced Building Techniques

3.2.1. Creating Rotated Buildings

Method 1: Rotation During Creation

  1. Start building creation normally

  2. After first click, hold Ctrl key

  3. Move mouse to set both size and rotation

  4. Click to complete

Method 2: Rotation After Creation

  1. Create building normally (rectangular)

  2. Select the building

  3. Hold Ctrl and drag corner handles to rotate

Rotation Reference Point: - Block buildings rotate around first corner (anchor) - Rotation angle displayed in status bar - Angles measured from positive X-axis (eastward)

3.2.2. Creating Building Complexes

Connected Buildings: 1. Create first building 2. With snap enabled, start second building from first building’s corner 3. Snap indicators will guide precise alignment

Courtyard Buildings: 1. Create outer perimeter buildings first 2. Use snap to align inner walls 3. Consider using Rectangle Select to modify multiple buildings

Regular Patterns: 1. Create one building as template 2. Use copy/paste operations (via selection and movement) 3. Leverage snap system for regular spacing

3.3. Building Properties

3.3.1. Default Properties

New buildings are created with default properties:

  • Stories: 3 floors

  • Height: 9.9 meters (3 floors × 3.3m default storey height)

  • Rotation: 0 degrees (aligned with coordinate axes)

  • Fill Color: Light gray (configurable)

  • Border Color: Dark gray (configurable)

3.3.2. Setting Initial Height

Keyboard Shortcuts: Press 1-9 immediately after creation to set stories

Height Dialog: 1. Select the building 2. Click “Set Height” button 3. Choose stories or enter exact height in meters

Storey Height Configuration: - Set default through Edit → Set Storey Height - Affects calculation: Total Height = Stories × Storey Height - Global setting for all new buildings

3.3.3. Building Identification

Automatic ID Assignment: - Each building gets a unique UUID identifier - IDs are used for export formats and data consistency - Invisible to user but important for file integrity

Visual Representation: - Height shown as text label (e.g., “3F” for 3 floors) - Label positioned at building center - White text with shadow for readability

3.4. Troubleshooting Creation Issues

3.4.1. Common Problems

Building Won’t Complete: - Check if second click is in valid area - Ensure minimum size requirements met - Verify not clicking on interface elements

Preview Not Showing: - Confirm you’re in building creation mode - Check zoom level (may be too far out) - Verify mouse is over canvas area

Snapping Not Working: - Check snap toggle is enabled - Ensure you’re within snap threshold - Other buildings must exist for corner snapping

Building Appears Wrong Size: - Check coordinate system and units - Verify basemap scaling is correct - Consider zoom level when judging size

Rotation Issues: - Hold Ctrl key while moving mouse - First click sets rotation anchor point - Release Ctrl to return to scaling mode

3.5. Quality Control

3.5.1. Validation During Creation

Size Validation: - Minimum building size: 1m × 1m - Maximum practical size: 1000m × 1000m - Warning for unusually large or small buildings

Position Validation: - Buildings can overlap (intentionally supported) - No automatic collision detection - Visual inspection recommended

3.5.2. Importing Reference Data

From AUSTAL Files: - Use File → Import from AUSTAL - Provides building positions and heights - Good starting point for atmospheric modeling

From Geographic Data (with GeoTIFF): - Load aerial imagery as reference - Trace building outlines visually - Match heights to shadow analysis or known data

3.5.3. Data Exchange Formats

CitySketch Native (.csp): - Preserves all editor settings - Includes color and display preferences - Best for continued editing

AUSTAL (austal.txt): - Atmospheric modeling format - Contains building geometry and properties - Used with AUSTAL simulation software