On a polygon object, blue is the positive
(outer) side of a surface and yellow/gold is the negative (inner) side
of a surface. (The Color Backfacing primitives in the Primitives Manager
can override those default colors.) The normal direction of the surface
is important for offset operations, and comparison shelling, NURBS creation,
and texture map generation.
Polygons > Flip Normals flips the normal direction of a polygonal surface, which may be helpful in downstream operations. It can be performed only on open-surface polygon objects.
The controls are:
Color Backfacing checkbox - whether to distinguish the normals by the use of color.
Flip All button - performs the flip immediately.
OK button - stores the object in the Model Manager.
Cancel button - terminates the dialog.
To use the Flip Normals command:
Select Flip Normals from the menu or click the icon.
Set the parameters.
Click on a triangle of the component to be flipped. All triangles connected to the clicked triangle become flipped. Or, press Flip All.
Click OK to exit the operation with the current changes, or click Cancel to exit the operation without keeping the current changes.