Graphics Programs Reference
In-Depth Information
Ortho Mode (ORTHO):
Constrains the crosshairs to horizontal and vertical
movement, which makes drawing
orthogonal
(straight horizontal and vertical)
lines easy
See Chapter 4 for instructions on how to configure these modes and Chapter 7 for
information about why, when, and how to use them in actual drawing operations.
Polar Tracking (POLAR):
Polar tracking causes the crosshairs to jump to
certain angles when you draw and edit objects. The default angle settings are mul-
tiples of 90 degrees, but you can specify other angle increments, such as 45 or 30
degrees. See Chapter 7 for instructions on specifying the polar tracking angles that
you prefer. Clicking the Polar button toggles polar tracking on and off. Ortho and
polar tracking are
mutually exclusive
— turning on one mode disables the other.
Object Snap (OSNAP):
Object snap is another AutoCAD tool for ensuring
precision drawing and editing. You use object snaps to grab points on existing ob-
jects — for example, the endpoint of a line or the center of a circle. Chapter 7 con-
tains detailed instructions on how to use this feature.
3D Object Snap (3DOSNAP):
With AutoCAD's enhanced 3D capabilities, an
extension of object snaps into the third dimension was a given (not in AutoCAD LT,
of course). Enabling this mode lets you snap to the precise center of a face, a ver-
tex, the midpoint of an edge, or a number of similar 3D points you can't get to with
regular object snaps.
Object Snap Tracking (OTRACK):
When you turn on
object snap tracking,
AutoCAD hunts in a more sophisticated way for points that are derived from ob-
ject snap points. Chapter 7 briefly describes this advanced feature.
Allow/Disallow Dynamic UCS (DUCS):
This one's for 3D object creation
(and so isn't included in AutoCAD LT). Most AutoCAD primitive objects, such as
lines, arcs, and circles, are planar, and you have to set an appropriate plane in
three dimensions if you want to work in 3D. You can set planes with the UCS com-
