Graphics Reference
In-Depth Information
Figure 15.22.
Parametric blending terminology.
tory of the sweep, but it is more generally other related
curves such as the intersection of the base surfaces or some
offsets of those. See Figure 15.22(c).
Profile curve:
A cross-sectional curve of the blending surface associated to
each point of its spine. It is usually a planar curve. Other
terms that have been used for this curve are “blending arc,”
“generator,” or “crossing curve.” See Figure 15.22(a).
Thumbweight:
This is a quantity associated to the shape of a profile curve
and measures its “fullness.” The closer the curve is to the
base surfaces, the higher one says that its thumbweight is.
See Figure 15.22(d).
Assignment:
One can define profile curves without spine curves, but then
one has to say which points correspond to which on the trim
lines. This correspondence is called assignment. See Figure
15.22(a).
Vida et al. divide parametric blending approaches into five categories:
(1) Rolling ball blends
(2) Spine-based blends
(3) Trimline-based blends
