18
AutoCAD and Its Applications—Advanced
The concept behind the right-hand rule can be visualized even better if you are
sitting at a computer and the AutoCAD drawing window is displayed. Make sure the
current drawing is based on the
acad.dwt
template. If the UCS icon is not displayed in
the lower-left corner of the screen, turn it on by using the
UCSICON
command. Now,
orient your right hand as shown in Figure 1-3 and position it next to the UCS (or WCS)
icon. Your index finger and thumb should point in the same directions as the Y and fi
X axes, respectively. Your middle finger will be pointing out of the screen directly fi
at you, representing the Z axis. See Figure 1-4. Notice the illustration on the right in
the figure. This is the shaded UCS icon. It is displayed when the visual style is not fi
2D
Wireframe. Visual styles are introduced later in this chapter.
The right-hand rule can be used to eliminate confusion when changing the orien-
tation of the UCS. For example, as you will learn in Chapter 4, a simple way to change
the UCS is to rotate it. The UCS can rotate on any of the three axes, just like a wheel
rotates on an axle. Therefore, if you want to visualize how to rotate about the X axis,
keep your thumb stationary and turn your hand either toward or away from you. If
you wish to rotate about the Y axis, keep your index fi nger stationary and turn your fi
hand to the left or right. When rotating about the Z axis, you must keep your middle
fi nger stationary and rotate your entire arm. fi
If your 3D visualization skills are weak or you are having trouble visualizing
different orientations of the UCS, use the right-hand rule. It is a useful technique for
improving your 3D visualization skills. Rotating the UCS around one or more of the
axes becomes easier once you begin drawing 3D objects. A complete discussion of
UCSs is provided in Chapter 4.
UCSICON
Ribbon
View
Coordinates
Show UCS Icon
Type
UCSICON
Figure 1-4.
Using the right-hand rule to visualize the X, Y, and Z axis directions.
Right-Hand Rule
X
Z
Y
WCS Icon 3D View UCS Icon