- Creating a New Drawing
- Model Space and Layout Space
- Communicating with AutoCAD
- Object Snaps, Ortho Mode, and Polar Tracking
- Grid and Snap
- Draw a Circle
- Navigating Around the Drawing
- Object Properties
- Dimension Styles
- Modifying Drawing Objects
- Grip Editing
- Introduction to Advanced Editing Techniques
- Cleaning Up Layout Space
- Plotting and Page Setups
- Chapter Summary
- Chapter Test Questions
Communicating with AutoCAD
When you create a drawing, you are placing AutoCAD objects in the drawing. There are different types of objects (lines, arcs, circles, text, etc.). Each type of object has a unique set of properties. When you create an object, AutoCAD will ask you to specify the various aspects of that object. This is done primarily through prompts for information at both the command line window and the cursor.
The Command Line
The command line window is at the bottom of the drawing area by default (see Figure 2-7). This is one place where AutoCAD communicates with you. When you select a tool, AutoCAD will display the command name in the command line and then prompt you for more information. The command line can be docked at the top or bottom of the drawing window and moved. It can also be turned off completely, but this is not recommended.
FIGURE 2-7 The command line window
Dynamic input (see Figure 2-8) uses a command prompt that moves with your cursor and provides instant, dynamic feedback as you move around the drawing. Dynamic input provides you with active, heads-up feedback that allows you to read and respond to AutoCAD’s prompts without changing focus away from your drawing. Dynamic input can be turned on and off by toggling the Dynamic Input button on the status bar.
FIGURE 2-8 Dynamic input
Whether you use dynamic input, the command line window, or both, the general process you’ll follow when creating drawing objects is this:
Start a command.
Read AutoCAD’s prompt.
Pick points and/or respond to prompts.
Press <Enter> or <Esc> to end the command.
Sometimes the AutoCAD prompts can be difficult to decipher. There are some general conventions that AutoCAD uses.
AutoCAD will ask you to specify a placement point (for example, the start point of a line or arc or the center point of a circle). You can specify a placement point by picking a point on the screen, typing in a coordinate, or using an object snap.
When there are multiple ways to create an object, AutoCAD will display a down arrow next to the dynamic input prompt (see Figure 2-8). Press the down arrow key to see the list of command options.
At the command line, options are enclosed in square brackets [ ] and are separated by a space. You specify an option by selecting it with your mouse or by typing in the blue highlighted capital letter(s) shown for that option. For example, when drawing a circle, AutoCAD gives you the following prompt and options:
Specify center point for circle or [3P 2P Ttr (tan tan radius)]:
In this example, AutoCAD is asking you either to specify the center point of the circle or to select one of three options (3P, 2P, or Ttr). To specify the Ttr option, you would either pick it with your mouse or type T and press <Enter>.
Keep in mind that when you specify a point or select an option, AutoCAD will continue to ask you for more information until it has everything it needs to create that object.
The dynamic input at the cursor should disappear, and you should now see the prompt “Type a command” displayed at the command line. This is AutoCAD’s way of letting you know that it is idle and ready for the next command.