- Chapter Objectives
- Introduction
- Using Isometric Snap
- Switching Isometric Planes
- Using COPY and Other Edit Commands
- Drawing Isometric Circles with ELLIPSE
- Drawing Text Aligned with Isometric Planes
- Drawing Ellipses in Orthographic Views
- Saving and Restoring Displays with VIEW
- Chapter Summary
- Chapter Test Questions
- Chapter Drawing Projects
This chapter is from the book
This chapter is from the book
This chapter is from the book
Drawing Isometric Circles with ELLIPSE
You can use the ELLIPSE command to draw true ellipses in orthographic views or ellipses that appear to be circles in isometric views (called isocircles in AutoCAD). In this exercise, you use the latter capability to construct a hole in the bracket.
ELLIPSE |
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Command |
ELLIPSE |
Alias |
El |
Panel |
Draw |
Tool |
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To begin, you should have the bracket shown in Figure 11-11 in your drawing.To draw an isocircle, you need a center point. Often, it is necessary to locate this point carefully using temporary lines, object snap tracking, or point filters. You must be sure that you can locate the center point before entering the ELLIPSE command.
In this case, it is easy because the center point is on a snap point.
- Type ellipse <Enter> at the Command prompt.
There is an Ellipse tool on the ribbon, but this automates an initial option and does not give you access to the Isocircle option.
AutoCAD prompts:
Specify axis endpoint of ellipse or [Arc/Center/Isocircle]:
The option you want is Isocircle. Ignore the others for the time being.
- Select Isocircle from the command line, or right-click and select Isocircle from the shortcut menu.
AutoCAD prompts:
Specify center of isocircle:
If you could not locate the center point, you would have to exit the command now and start over.
- Use the Snap Mode and Grid Mode tools to specify the center of the ellipse, as shown in Figure 11-12. If you have drawn your object with the suggested dimensions, the center point will be over 2 units and back 2 units from the top-front corner of the bracket.
Figure 11-12 Ellipse isocircle
AutoCAD presents you with an isocircle to drag, as in the CIRCLE command. The isocircle you see depends on the isoplane you are in. To understand this, try switching planes to see how the preview changes.
- Drag the cursor to define the radius of the isocircle and then press <F5> to switch isoplanes. Observe the isocircle. Try this two or three times.
- Switch to the top isoplane before moving on.
AutoCAD prompts for a radius or diameter:
Specify radius of isocircle or [Diameter]:
A radius specification is the default here, as it is in the CIRCLE command.
- Specify a point so that your isocircle resembles the one in Figure 11-12.
Next, you use the COPY and TRIM commands to create the bottom of the hole.
- Start the COPY command.
- Select the isocircle.
- Right-click to end object selection.
- Specify the top-front corner of the bracket.
Any point can be used as the base point. By specifying the top-front corner, the bottom-front corner gives you the exact thickness of the bracket.
- Specify the bottom-front corner. Make sure you are in an isoplane that allows movement from top to bottom (the left or right isoplanes).
Your drawing should now resemble Figure 11-13. The last thing you must do is trim the hidden portion of the bottom of the hole.
Figure 11-13 Copy isocircle
- Press <Enter> to exit COPY.
- Start the TRIM command.
- Select cuTting edges from the command line, or right-click and select cuTting edges from the shortcut menu.
- Select the first isocircle as a cutting edge.
It may help to turn off snap to make these selections.
- Right-click to end cutting edge selection.
- Select the hidden section of the lower isocircle.
- Press <Enter> to exit TRIM.
The bracket is now complete, and your drawing should resemble Figure 11-14.
Figure 11-14 Trimming lower isocircle
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