Polygons > Cross Section [Copy to NURBS > Cross Section] creates a two-dimensional outline of a three-dimensional object where that object intersects a plane, or multiple parallel outlines where the object intersects multiple parallel planes, and stores outline(s) in a Curves object. The resulting Curves object can be further manipulated by functions on the Curve Menu, converted to boundary lines in a later phase, or utilized by another application.
To create a Curves object, highlight a polygon object in the Model Manager and click Polygons > Cross Section.
The controls on the Cross Section dialog are:
Align Plane group - allows the specification of a plane that appears superimposed on the object in the Viewing Area. See Methods of Superimposing Planes.
Multiple Sections group - controls the simultaneous creation of multiple parallel cross sections in a single Curves object
Sections dropdown - specifies the number of parallel planes and therefore the number of parallel cross sections that will be created.
Spacing field - specifies the distance between the multiple planes and therefore the spacing between cross sections.
Layout dropdown (Centered or One Way) - specifies whether the multiple planes and cross sections will be centered around the one visible plane, or stacked on one side of the visible plane.
Flip button (applicable when Layout is One Way) - causes the multiple planes and therefore the multiple cross sections to be stacked on the other side of the visible plane.
Curve Properties group -
Name field - specifies the name of the resulting Curves object in the Model Manager.
Crease Angle field - specifies the angle between polygons that causes one Curve object to end and another to begin. An angle greater than this value causes a new Curve object to be created. Contiguous polygons that join at this angle (or less) are represented by a single Curve object.
Fitting dropdown (Distance, Tolerance, or Constant) - specifies a method of creating control points on the individual curves that comprise the Curves object. For details, see the controls of the Curve > Edit Curves function. Depending on this setting, one of the following appears:
Distance field - specifies a fixed distance between control points along the cross section line.
Tolerance field - specifies that control points be placed along the cross section line such that the line cannot diverge from the actual object at any position by more than this value.
Control Points field - specifies a fixed number of control points along the cross section line.
Tension field - adjusts the tension on the segments between control points, affecting the overall smoothness of the cross section line.
Compute button - computes cross sections.
Next button - prepares the dialog for the placement of additional planes and the creation of additional cross sections in the Curves object named Name.
OK button - saves all computed cross sections to the Model Manager in a Curves object named Name.
Cancel button - terminates the dialog without saving any cross sections to the Model Manager.