Graphics Programs Reference
In-Depth Information
have different z-values. Splines are a better option than 3D polylines for sweeps
because they can have smoother curves.
Helixes.
Helixes can be either 2D (think of a mosquito coil, or the element on an
electric range) or 3D (think of Mr. Slinky). Helixes are especially useful as paths for
threaded objects.
You can find the LINE, 3DPOLY, and SPLINE commands on the Draw panel of the Rib-
bon's Home tab; the HELIX command is on that panel's slideout.
The 3DPOLY command is similar to the PLINE (plain old 2D polylines) com-
mand. Both commands draw a series of connected line segments, but they have
different capabilities:
The 3DPOLY command accepts 3D points for the line segments' vertices. The
PLINE command requires that all vertices be on the same plane.
3DPOLY is limited to straight line segments. PLINE can draw arc segments and cre-
ate segments with uniform or tapered width.
Segments created with 3DPOLY can't display dash-dot linetypes; 3D polyline seg-
ments always display as continuous lines.
The command sequence for drawing 3D segments with the LINE or 3DPOLY command is
the same as for drawing 2D segments with the LINE or PLINE command; see Chapter 8 if
you need a refresher on drawing lines. The only difference is that you specify 3D co-
ordinates instead of 2D ones. Figure 22-6 shows an example.
