Graphics Programs Reference
In-Depth Information
FiGuRE 5.2
The object with the dark blue grips is a polyline, and
the object with the light blue grips is an alignment. Alignments have more
types of grips that enable more geometric editing functionality.
Alignments Are Smarter
As you investigate the grip-editing behavior of the alignment versus the polyline,
what do you find? You should notice that the alignment wants to follow a very
basic geometric rule that the polyline doesn't worry about too much: maintain-
ing tangency. Whether you move or stretch a straight line portion (aka tangent)
or modify a curve, the adjacent lines and curves morph themselves to remain
tangent (shown here). This is a good thing because driving your car down a road
where the curves and lines aren't tangent could be hazardous to your health.
Tangency
Maintained
Radius
Changed
Automatically
Edit
PT Moved
Automatically
