8

Surf ace Modifier 837
3.
Choose Modifiers menu > Patch/Spline Editing
> Surface from the Modifier List.
Notice that the three- and four-sided splines
formed patches but the five-sided NG on did
not. Thefive-sidedsplinedoesnotforma
three- or four-sided closed region. To make it
a valid spline, a line must bisect the NGon to
form a three- and four-sided region.
4. In the stack display, choo se the Edit Spline
modifier again. Turn on Create Line on the
Geometry rollout, and create a line that bisects
the five-sided NGon.
The start and end points of the line should
overlap the vertices on the NGon. Being exact
is not cr itical; the T hreshold parameter fuses
spline vertices based on their proximity.
5. In the stack display, choose the Surface modifier
again. Now t he five-sided NGon is a patch
object, consisting of a quad patch and a tri
patch.
Note: Ifthesplineobjectdidnotturninto
a patch, increase t he Surface modifier’s
Threshold parameter until the patches appear.
Exa mple continued: Adj usting the sha pe of the
spline:
1.
In the stack display, expand the Edit Spline
modifier’s hierarchy, and choose t he Vertex
sub-object level.
2. In the Top viewport, select the top vertex of the
five-sided NGon.
Two vector hand les are displayed. These
handles can b e moved on any axis.
3. Turn on Select and Move on the toolbar,
then drag the handles around in the Top
view por t.
Theshapeofthesplinechanges.
4. Belowthestackdisplay,turnontheShow
End Result On/Off Toggle button.
The patch changes shape to fit the spline.