8

1248 Chapter 9: Sur face Modeling
Inter face Iso Parametric Lines group
The controls in this group box affect the display of
the NURBS surfaces in viewports.
ULinesandVLines—The number of lines used to
approximate the NURBS surfaces in viewpor ts,
along the surface’s lo c a l U and V dimensions,
respectively. Reducing these va lues can speed up
thedisplayofthesurface,butreduceaccuracy
of the display. Increasing these values increases
accuracy at the expense of time. Setting one of
these values to 0 displays only the edge of the
object in the corresponding dimension.
Iso Only—When chosen, all viewports display iso
line (page 3–1053)
representations of the surface.
Iso (parametr ic) lines are similar to contour lines.
ThelinesshowwheretheNURBSsurfacehas
a constant U value or V value or both. Iso line
representations can be less crowded and easier to
visualizethanwiremeshrepresentations.
Iso a nd Mesh—(The default.) When chosen,
wireframe viewports display iso line
representations of the surface, and shaded
view por ts display the shaded surface.
Mesh Only—When chosen, wireframe viewports
display the surface as a wire mesh, and shaded
view por ts display the shaded surface.
In wireframe viewports, this option lets you see
the surface approximation used for viewports.
Iso and m esh displays of a NURBS teapot