Overview
This module teaches the basic CAD (Computer-Aided Design) drawing commands in AutoCAD for technical drafting, focusing on their functions, usage, and practical application.
Learning Objectives and Overview
- Identify different AutoCAD drawing commands and their functions.
- Use drawing commands to complete plate exercises.
- Choose appropriate commands for effective and creative drafting.
Basic Drawing Commands
- Line (L) Draws a straight line between two points.
- Construction Line (XL) Generates an infinite line through two points, useful for layouts and grids.
- Polyline (PL) Creates a continuous line composed of multiple segments that act as a single object.
- Rectangle (REC) Draws vertical-horizontal rectangles by selecting two diagonal corners or specifying dimensions.
- Polygon (POL) Creates regular polygons (3-1024 sides), defined by center, size, and orientation.
- Circle (C) Draws circles using center/radius, center/diameter, 2 or 3 points, or tangent options.
- Arc (A) Draws arcs using combinations of start, center, end, or specific points.
- Ellipse (EL) Creates ellipses by specifying axes or center, or makes elliptical arcs.
- Hatch Fills a closed area with a pattern or solid fill for section views.
- Wipe Out Masks part of a drawing for clarity (e.g., for adding text over complex areas).
- Helix Draws 2D or 3D spiral objects.
- Revision Cloud Creates a cloud-shaped annotation, often as a rectangle, to indicate drawing revisions.
Usage and Shortcuts
- Drawing commands can be accessed via command line, toolbar, or menu.
- Right-clicking and selecting "Enter" or using the Spacebar can repeat the last command.
- Use a separate sheet for all exercises and follow instructions carefully.
Types of Circles and Polygons
- Center/radius, center/diameter, 2-point, 3-point, tangent options for circles.
- Polygons can be inscribed (vertices touch circle) or circumscribed (edges touch circle).
Applying Commands: Sample Exercise Steps
- Use the Rectangle command to create a 2x2 square.
- Draw center and diagonal lines inside the rectangle using Line.
- Save files in the required format as practice.
Key Terms & Definitions
- Command Line — Text area where commands are entered and prompts are shown.
- Crosshair — Cursor for selecting and drawing in AutoCAD.
- Polyline — Connected sequence of line or arc segments functioning as one object.
- Construction Line — Infinite lines used for creating reference frameworks.
- Wipeout — Tool for masking parts of a drawing to improve clarity.
- Revision Cloud — Markup indicating changes or corrections in a drawing.
Action Items / Next Steps
- Complete the pretest and all in-module activities and exercises.
- Practice using each drawing command in AutoCAD or via written descriptions if software is unavailable.
- Draw a flowchart for border management using basic CAD shapes (as described in the additional activity).
- Review answer key and self-assess learning using the module’s posttest.