Use of AutoCAD Command 01

5.2.1 Example 1 draw the pressure gauge

Step 1 Create a new graphics file

Start the AutoCAD 2002 system and create a new graphics file for the template "ACADISO.DWT".

Step 2 Draw the contour of the pressure gauge

(1) First use the "Circle" command to draw a circle with a point (100,100) as the center, 50 as a radius, and then invoke the "Rectang" command to draw a rectangle between the point (85,45) and the point (115,155). The result is shown in Figure 5-1.

(2) Now use the "trim" command to remove the rectangular part of the circle. Select the icon in the Modify toolbar and follow the prompts to:

Command: _trim
Current Settings:projection=ucs, Edge=none Select Cutting Edges ...
Select Objects:1 found	Select a circle as the trimming boundary
Select Objects:enter	To determine the clipping boundary that you select
Select object to trim or shift-select to extend or [Project/edge/undo]:
	Select segments to trim within a circle
Select object to trim or shift-select to extend or [Project/edge/undo]:
	Select another segment to trim within a circle
Select object to trim or shift-select to extend or [Project/edge/undo]: Enter
	End Trim Command

Step 3 Draw the Dial

(1) Draw the other two circles. Instead of using the "circle" command to draw, you can use the offset command to generate a new circle directly from an existing circle. For illustration purposes, the circle drawn in the previous step is called Circle 1, and the circle drawn in this step is called Circle 2 and Circle 3, respectively. Select the icon in the Modify toolbar and follow the prompts to:

Command: _offset
Specify offset distance or [through] <through>: 5 Enter	Specify an offset distance of 5
Select object to offset or <exit>:	Select Circle 1 as the offset object
Specify point on side to offset:	Select any point in Circle 1 to specify the offset direction
Select object to offset or <exit>: Enter	End Offset Command

In this way, the Circle 2 with the same center is generated by the offset operation of the Circle 1, as shown in Figure 5-3.

(2) The "offset" command is now used to generate Circle 3 from Circle 2. Select the icon in the Modify toolbar and follow the prompts to:

Command: _offset
Specify offset distance or [through] <5.0000>: 3 Enter	Specify an offset distance of 3
Select object to offset or <exit>:	Select Circle 2 as the offset object
Specify point on side to offset:	Select any point in Circle 2 to specify the offset direction
Select object to offset or <exit>: Enter	End Offset Command

When you are done, the result should look like Figure 5-4.