9

Surface Approximation Rollout 1247
Iso Parametric Lines group
Thecontrolsinthisgroupboxaffectthedisplayof
the NURBS surfaces in viewports.
ULinesandVLines—The number of lines used to
appro ximate the NURBS surfaces in viewports,
alongthesurface’slocalUandVdimensions,
respectively. Reducing these va lues can speed up
the display of the surface, but reduce accur a cy
of the display. Increasing these va lues increases
accuracy at the expense of time. Setting one of
these va lues to 0 displays only the edge of the
object in the corresponding dimension.
Iso Only—When chosen, all viewports display iso
line (page 3–959) representations of the surface.
Iso (parametric) lines are similar to contour lines.
ThelinesshowwheretheNURBSsurfacehas
a constant U value or V value or both. Iso line
representations can be less crowded and ea sier to
visualize than wire mesh representations.
Iso and Mesh—( The default.) When chosen,
w i reframe viewports display iso line
representations of the surface, and shaded
viewports display the shaded surface.
Mesh Only—When chosen, wireframe viewports
display the surface as a wire mesh, and shaded
viewports display the shaded surface.
In wireframe viewports, this opt ion lets you see
the sur face approximation used for viewports.
Iso and mesh displays of a NURBS teapot
Viewports—When chosen, the utilit y affects how
surfaces in the NURBS objec ts are displaye d
interactively in viewports, including shaded
viewports, and by the preview renderer.
The Viewports surface sett ings are also used when
youapplyameshmodifiersuchasMeshSelectto
the NURBS objects. This is import ant b ecause it
can affect the scene’s geometry.
Render er —When chosen, the utilit y affects how
surfaces in the NURBS objects are display ed by
the renderer, and by the draft renderer for Quick
Render.
Base Surface—When on, settings affect entire
surfaces in the select ion set. Default=on.
Surf ace Edge—When on, settings affect the
tessellation of sur face edges that are defined by
trim curves.
Displaced Surface—Enabled only when Renderer
is chosen. Turn on to set a third, independent
approximation setting for surfaces that have a
displacement map (page 2–1511) or Displace (page
1–629) modifier applied to them.
Load Tessellation Preset group
Lets you choose a preset low, medium, or
high-quality level of surface approximation. While
a preset is chosen, the values it uses are displayed
in the Tessellation Method group box.
Preset va lues are saved in the 3dsmax.ini file.
You can customize the preset values by using
the buttons in the follow i ng group box, Save
Tessellation Preset.
Low—Selects a (comparatively) low-quality level
of surface approximation. These are the default
values:
Viewpor ts, Ba se Surface:
Method=Spatial and Curvature
Edge=50.0