Learning Technical Drawing with CAD: Understanding the Basics
Learn about CAD functionality, drawing techniques, and AutoCAD usage in technical drawing. Get insights on creating accurate drawings, utilizing commands efficiently, and setting up drawings. Practice exercises included!
Learning Technical Drawing with CAD: Understanding the Basics
E N D
Presentation Transcript
Class11_1 Today: • Technical drawing using CAD
Reminders: Dates Design demonstration is 3.5 weeks from today. It goes fast! Remember advice of previous classes: “Leave lots of time for testing.” Questions?
CAD • CAD is a tool to help you make technical drawings; you must make the drawings • Using CAD is not the same as doing design
CAD • Can be highly accurate • Allows easy repetition and revision • Provides input to other analyses and manufacturing programs
CAD • Drawings are full scale (true size units) • Objects (such as lines) have numerically defined properties, such as end-point coordinates
CAD • The drawing is more than its appearance—it is a numerical description of the geometry (example: lines do not just appear to connect, they share the same end point coordinates)
CAD Bottom line…. A CAD file is a NUMERICAL DATABASE describing your part. It is not a picture. Need to adopt this mindset when making a CAD drawing.
AutoCAD • New users beware: in AutoCAD there are usually about 5 ways to accomplish the same thing; this can be confusing at first • Tip: learn to use the command line and depend less on the mouse • Tip: read the help files because there are lots of details and tricks to learn
Let’s take a look at AutoCAD • Graphics area • Command line • Toolbars • Pull down menus • Dialog boxes • Status bar and drawing aids • Model vs. layout space
AutoCAD • The free student version is available from Autodesk • We will use the AutoCAD Classic interface.
AutoCAD • Draw commands • Draw commands create objects • Remember: you are creating a numeric object, not just lines on a screen… • Many ways to accomplish the same thing
AutoCAD • Help files • Spacebar same as enter • Hit ESC to cancel current command • Drawing aid: ortho
AutoCAD • Ways to specify coordinate points: • Pick (interactive with mouse) • Absolute X,Y • Relative rectangular @X,Y • Relative polar @distance<angle • Direct distance
Exercise 1 • Draw the following lines using the procedure suggested…
Circles and Arcs • Can be drawn with a variety of options • Notice the use of the Command Line • Examples • Center, radius • Center, diameter • Two points • Tangent, tangent, radius
AutoCAD • Modify commands • Selection sets • Oops • Undo
Exercise 2 • Draw a bunch of circles • Try selection set methods • Experiment with Erase • Remember: use Esc to abort a command • Experiment with Oops and Undo
AutoCAD • Setting up drawings • Limits • Zoom window, zoom previous • Zoom all
Drawing aids • ORTHO to restrict only horz/vert lines • OBJECT SNAP enables the cursor to “snap” to existing object features, such as end points • Types of object features to snap to • Running OSNAP • Command line OSNAP
More AutoCAD functionality • Construction line type • More Modify commands: Fillet, Offset • More Modify commands: Mirror
Exercise • Draw top item on the handout • Do not include dimensions • If you already know how to do this, help a person sitting near you.
More AutoCAD: Layers • Layers • Tip: the availability of layers is a great feature of CAD…learn to use layers effectively (use lots of them) • Do not draw on the 0 layer or the defpoints layers. These have special properties and should be reserved for that use.
Example of using layers • Set up layers in preparation for drawing Layers: • Part, black, continuous • Construction, light grey, continuous • Center line, black, centerline style