2D CAD tools & sketching
Graphic Communication · Higher · mrkellydt.co.uk
What you're learning in this topic
Learning intention WALT
We are learning about 2D CAD tools & sketching, specifically to:
know
- 2D CAD tools from a sequence of changes: line, trim, mirror, rotate, scale, fillet, chamfer
understand
- the use of CAD libraries
- 2D constraints: linear, radius, diameter, perpendicular, parallel, fixed, tangent, concentric
be able to
- use offset, extend, array and project edge
Success criteria WILF
- I can name 2D CAD tools from a sequence of changes: line, trim, mirror, rotate, scale, fillet, chamfer
- I can explain the use of CAD libraries
- I can use offset, extend, array and project edge
- I can explain 2D constraints: linear, radius, diameter, perpendicular, parallel, fixed, tangent, concentric
2D drawing tools
| Tool | What it does |
|---|---|
| Line, circle, arc, ellipse, rectangle | Draw basic geometry |
| Trim | Cuts away parts of lines up to where they cross other lines |
| Mirror | Makes a reflected copy about a line: draw half, mirror the rest |
| Copy | Duplicates geometry |
| Rotate | Turns geometry about a point |
| Scale | Makes geometry bigger or smaller |
| Zoom | Changes the view, not the size of the drawing |
| Fillet | Rounds a corner with a set radius |
| Chamfer | Cuts a corner off at an angle, e.g. 4 × 45° |
| Pattern fill (hatch) | Fills an area with a pattern, e.g. section hatching |
Exam questions show a sketch changing in stages and ask you to name the tool used at each stage: line, trim, mirror, rotate and scale come up most.
Higher 2D tools and constraints HIGHER
- Offset: a parallel copy of a line or curve at a set distance, e.g. offset 12 to make a wall thickness.
- Extend: lengthens a line to meet another.
- Array: linear, box (rectangular) or radial copies; state the number of instances and the spacing or angle.
- Project edge: brings edges of existing 3D geometry onto the current sketch.
2D constraints fix the geometry so it can't change by accident: linear, radius and diameter (dimensional), and perpendicular, parallel, fixed, tangent and concentric (geometric). A fully constrained sketch updates predictably when one size is edited.
CAD libraries and import/export
A CAD library holds ready-made parts and symbols (nuts, bolts, bearings, doors, windows, sanitary ware). Using it saves time because parts aren't redrawn, and they are accurate and standard. Import brings in files such as images or another package's drawings; export saves to formats others can use.
Key terms
| Trim | Removes parts of lines up to where they meet other lines. |
|---|---|
| Mirror | Creates a reflected copy about a line. |
| Fillet (2D) | Rounds a corner to a set radius. |
| Chamfer (2D) | Cuts a corner at an angle. |
| CAD library | Ready-made standard parts and symbols; saves time and is accurate. |
| Offset | Creates a parallel copy at a set distance. |
| Radial array | Copies a feature a set number of times around a centre. |
| 2D constraint | A rule fixing sketch geometry, e.g. tangent, concentric, parallel or a dimension. |
Quick check
1. Which tool removes the overlapping parts of crossing lines?
- Trim
- Mirror
- Scale
- Copy
Show answer
2. A designer draws half a symmetrical shape. Which tool completes it?
- Rotate
- Mirror
- Fillet
- Zoom
Show answer
3. Which tool rounds a sharp corner?
- Chamfer
- Trim
- Fillet
- Mirror
Show answer
4. Zoom changes…
- The size of the object
- The line type
- The scale on the drawing
- The view only
Show answer
5. Which tool makes a parallel copy 12 mm away?
- Offset
- Mirror
- Extend
- Project edge
Show answer
6. Which constraint makes two circles share a centre?
- Tangent
- Concentric
- Parallel
- Perpendicular
Show answer
Printable worksheet
An I do, we do, you do worksheet for this topic, with a separate answer sheet.