8

1234 Chapter 9: Sur face Modeling
ZIP tab
This tab chooses the zip algorithm. Zipping
concatenates the CV lattices of the two original
curves. Zipping can change the shape of the
original curves, but usually it produces a better
result than joining.
By default, the ZIP tab is active.
If both curves are untrimmed point curves, the
result of zipping is a point curve. In all other c ases,
the result is a CV curve.
Tolerance—Adistancein3dsMaxunits. Ifthe
ends of the two original curves are closer than this
distance, zipping deletes one of the points or CVs
in order to avoid creating coincident points or CVs
in the new zipped curve.
Tension 1—(Disabled.)
Tension 2—(Disabled.)
Join tab
This tab chooses the join algorithm. J oining first
creates a blend curve between the two origi nal
curves, and then makes all three into a sing le
curve.Joiningdoesnotchangetheshapeofthe
two original curves.
If both curves are p oint curves, the result is a point
cur ve. If one or both cur ves are CV curves, the
result is a CV curve.
Tolerance—Adistancein3dsMaxunits. Ifthe
gap between the curves you are joining is g reater
than this value, the join is created by first creating
ablendcurveandthenjoiningthethreeparts.If
the gap is less than this value, or if the curves are
overlapping or coincident, the sof tware doesn’t
create the blend.
Creating a blend and then joining the three curves
into a single curve is the better technique. The
result matches the parent curves well. Without the
blendstep,theresultingcurvecandeviatefromthe
parent curves, i n order to maintain smoothness.
(The amount of deviation depends on how far
from tangent the two input curves were at the join.)
A problem arises when the gap is too small. In this
case, the software generates the blend but because
there isn’t enough room for it, the resulting curve
has a loop. To avoid having this loop, set the
Tolerance higher than the gap distance.
Ifyousetthetoleranceto0.0,thesoftwarechooses
avaluetousefortheTolerance.
Tension 1—Adjusts the tension of the new curve at
the end of the first curve you picked.
Tension 2—Adjusts the tension of the new curve at
the end of the second cur ve you picke d.
Prev iew—When on, the effect of the zip or join is
previewed in viewports. Default=on.
Join Surfaces Dialog
Modify panel > Select NURBS surface sub-object. >
SurfaceCommonrollout>Joinbutton>Jointwo
sur f ace s in a vie w p ort.
This dialog lets you choose the way to join two
surfaces.
Interf ace