8

Convert Surface Dialog 1229
From U a nd V Iso L ines—
Uses curves f rom both the
UandVdimensionstoconstructaUVloft.
UCurves—Sets the number of curves in U.
VCurves—Sets the number of curves in V.
Use Point Curv es—When on, constructs the loft
from point curves instead of the default CV curves.
Default=off.
Ex tr a Points per S egment—This control is available
only for UV lofts (From U and V Iso Lines). Lets
you increase the number of points in each segment.
Fuse Po in ts—This control is available only for
UV lofts (From U and V Iso Lines). When on,
fusespointsatcurveintersectionstoensurethat
the U and V curves continue to intersect when
you edit the sur face, and that the surface remains
coincident with its parent curves. UV lofts
constructed from intersecting curves behave more
predictably. Default=on.
Fit Point tab
If the sur face isn’t already a point surface, this tab
converts it to a point surface.
In U—Sets the number of point rows (in the
surface’s U axis).
In V —Sets the number of point columns (in the
surface’s V axis).
Tolerance—When chosen, the software calculates
the number of points. This option rebuilds the
surface according to accuracy. The lower the
Tolerance v alue, the more accurate the rebuild.
Increasing Tolerance enables the surface to be
rebuilt using fewer points.
CV Surface tab
If the surface isn’t already a CV surface, this tab
conv erts it to a CV surface.
This tab is the default.
Number —When chosen, the spinners set the
number of CVs in the CV surface.
In U—Sets the number of CV rows (in the surface’s
U axis).
In V —Sets the number of CV columns (in the
surface’s V axis).
Tolerance—When chosen, the software calculates
the number of CVs. This option rebuilds the
surface according to accuracy. The lower the
Tolerancevalue,themoreaccuratetherebuild.
Increasing Tolerance enables the surface to be
rebuilt using fewer CVs.
Reparameterization group
These controls let you reparameterize the CV
surface and turn on automatic reparameterization.
Chord Len g th—Chooses the chord-length
algorithm for reparameterization.
Chord-length reparameterization spaces knots
(in
parameter space (page 3–1082) )basedonthe
square root of the length of each seg ment.
Chord-length reparameterization is usually the
best choice.
Unifor m—Spaces the knots uniformly.
A uniform knot vec tor has the advantage that the
surface changes only locally when you edit it. With
chord-length parameterization, moving any CV
canpotentiallychangetheentiresurface.
Maintain Para meterization—When on, the
surface is automatically reparameterized
as you edit it, using the currently active
method of repara meterization. When off, no
reparameterization happens unless you use a
dialog to specifically request it. Default=on.
Prev iew—When on, viewports display a preview of
the convers ion. Turning off this toggle can speed
up conversion, especially to lofts.