- 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
The ELLIPSE command can be used to draw true ellipses in orthographic views or ellipses that appear to be circles in isometric views (called isocircles in AutoCAD). In this task, we use the latter capability to construct a hole in the bracket.
isocircle: The elliptical representation of a circle in an isometric drawing.
ELLIPSE |
|
|---|---|
Command |
Ellipse |
Alias |
El |
Panel |
Draw |
Tool |
|
✓ To begin this task you should have the bracket shown in Figure 11-11 on your screen.
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 our case, it is easy because the center point is on a snap point.
✓ Type el <Enter>.
There is an Ellipse tool on the ribbon and an Ellipse selection on the Draw menu, but these automate an initial option and do not give you access to the Isocircle option.
AutoCAD prompts:
Specify axis endpoint of ellipse or [Arc Center Isocircle]:
The option we want is Isocircle. Ignore the others for the time being.
✓ Select Isocircle from the command line.
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 pick the center of the surface, 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 gives you 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 image changes.
✓ Stretch the isocircle image out 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.
✓ Pick a point so that your isocircle resembles the one in Figure 11-12.
Next, we use the COPY and TRIM commands to create the bottom of the hole.
✓ Enter the COPY command.
✓ Select the isocircle.
✓ Right-click to end object selection.
✓ Pick the top front corner of the bracket.
Any point can be used as the base point. By picking the top front corner, the bottom front corner gives you the exact thickness of the bracket.
✓ Pick the bottom front corner. Make sure that you are in an isoplane that allows movement from top to bottom (the left or right isoplanes).
Your screen should now resemble Figure 11-13. The last thing we must do is trim the hidden portion of the bottom of the hole.
Figure 11-13 Copy isocircle
✓ Press <Enter> to exit COPY.
✓ Enter the TRIM command.
✓ Pick 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 screen should resemble Figure 11-14.
Figure 11-14 Trimming lower isocircle
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