Grade 10 building construction Related Drawing – Computer Aided Drawing Notes
Related Drawing — Computer Aided Drawing (CAD)
Subject: Building Construction | Subtopic: Computer Aided Drawing
Target age: 15 years (Kenyan context)
Specific Learning Outcomes
- a) Identify types of CAD software used in building drawing.
- b) Set up a CAD drawing environment on a digital device.
- c) Draw plane shapes using CAD software.
- d) Appreciate the importance of CAD in building drawing.
Introduction (short)
CAD (Computer Aided Drawing) uses a computer to make accurate building drawings and plans. At 15, you will learn common CAD programs, how to prepare your workspace, draw basic plane shapes (lines, rectangles, circles, polygons) and understand why CAD is important in building construction in Kenya.
1. Types of CAD software used in building drawing (examples)
- AutoCAD — widely used for 2D drafting and detailed construction drawings.
- SketchUp — simple 3D modelling; good for concept designs and quick models.
- Revit — Building Information Modelling (BIM) for detailed building models and schedules.
- ArchiCAD — BIM-focused, used by many architects for building projects.
- LibreCAD — free 2D CAD for basic drafting (useful in schools with limited budgets).
- MicroStation / BricsCAD — professional CAD packages used by engineers.
Note for Kenyan learners: many architects and engineers in Kenya use AutoCAD, Revit and SketchUp. Free or student versions are often available for learning.
2. Setting up a CAD drawing environment (step-by-step)
- Hardware & software: use a computer with enough memory, mouse with a scroll wheel, and a monitor with good resolution.
- Install the CAD program: follow installer instructions or use school/licensed versions. Keep software updated.
- Create a new drawing: File → New. Choose a template if available (architectural or metric).
- Set units: set units to meters (or millimetres) depending on local practice. Example: UNITS → Decimal → metres.
- Set drawing limits/scale: set a suitable drawing area (e.g., 0–100m) and choose a paper/plot scale later (1:100, 1:50 etc.).
- Layers: create layers for walls, doors, windows, furniture, dimensions, text. Give each layer a colour and line type.
- Grid, Snap & Ortho: turn on Grid and Snap if needed; Ortho helps draw straight horizontal/vertical lines.
- Object snap (OSNAP): enable endpoints, midpoints, intersections to draw accurately.
- Save and backup: save work often and keep backups (USB, cloud). Use meaningful file names (e.g., 3RoomPlan_YourName.dwg).
3. Drawing plane shapes in CAD (basic exercises)
Common tools: Line, Rectangle, Circle, Arc, Polygon, Trim, Extend, Offset, Move, Copy.
Simple practice: draw a small 3-room plan (example steps)
- Set units to metres. Decide wall thickness (e.g., 0.15 m).
- Use Rectangle or Line to draw outer walls: draw rectangle from (0,0) to (8,6) — this becomes building outline (8m × 6m).
- Use Offset tool to create inner wall line at 0.15m inward for wall thickness.
- Draw internal partition walls with Line tool, using Ortho for straight lines.
- Insert door openings by trimming and leaving gaps (e.g., 0.9 m for a single door).
- Draw windows as thinner rectangles on walls (e.g., 1.2 m wide).
- Add furniture using simple rectangles to show layout (bed, table) — this helps checking space and circulation.
Visual: basic plane shapes (SVG)
4. Importance of CAD in building drawing
- Accuracy: precise measurements reduce errors on site.
- Speed: faster drawing, editing and copying than hand-drafting.
- Easy revisions: modify a design quickly without redrawing everything.
- Visualization: convert 2D plans to 3D to see how a building will look.
- Collaboration: share digital files with architects, engineers, and contractors.
- Documentation: produce drawings, schedules and quantities useful for costing and compliance with Kenyan building regulations.
Suggested learning experiences (class activities)
- Teacher demo: show a short demo (10–15 minutes) of AutoCAD or SketchUp basic tools: Line, Rectangle, Circle, Offset.
- Guided practice: students follow steps to set units and draw a simple floor plan (3-room house) in pairs.
- Hands-on assignment: draw a classroom plan to scale (measure a real classroom if possible) and submit the DWG or PDF.
- Software comparison: small groups research one CAD program and present advantages/disadvantages for Kenyan builders.
- Field link: invite a local architect/engineer or watch a short video showing CAD use in a Kenyan building project.
- Peer review: exchange drawings and give feedback on clarity, layer use, and dimensions.
Assessment ideas
- Formative: teacher checks saved files for correct units, layers and basic shapes.
- Summative: produce a scaled 2D plan of a simple house with dimensions and a short report explaining the CAD setup and tools used.
- Practical test: timed exercise to draw specified plane shapes to given measurements.
Safety, ethics and tips
- Always save frequently and keep backups (cloud or USB).
- Respect software licenses — use student or school versions where available.
- Label layers clearly and keep your drawing tidy for easier teamwork and printing.
Use these notes as your classroom guide. Practise often in the computer lab and ask your teacher for projects tied to real Kenyan settings (e.g., local house plans, school buildings).
Prepared for: Building Construction — Related Drawing (CAD). Teacher may adapt to available software and school resources.