VRTX Basic Creation Method

The OUTL and VRTX elements can be created and deleted in the usual manner, for example,

NEW OUTLine

NEW VRTX AT @

DELETE VRTX

The position of a VRTX and the shape of the span drawn to it from the previous VRTX are defined by the SPAN command. The command is valid at any VRTX except the first in list order. Variations of the SPAN command are:

SPAN TO position

Vertex point defined by <position>

SPAN THROUGH position

Span defined as a circular arc passing through position. Defines BULG.

SPAN DIMTO CLOSE

Vertex point coincident with starting vertex.

SPAN STRAIGHT DIMTO position

Straight line span with vertex at <position>

SPAN RADIUS value

Set radius of circle of which (arc) span forms a part. Converts straight line span to an arc.

SPAN ASUB value

Sets angle subtended by (arc) span. Converts straight line span to an arc.

SPAN BY xypos

Move the two VRTXS of the current span by the given displacements.

SPAN DRAG BY xypos

Move the two VRTXS and all connected drafting primitives of the current span by the given displacements.

position can be a Design p-point, a 3D point or an explicit Sheet coordinate. A cursor hit can be used with all except the CLOSE, RADIUS, ASUB and STRAIGHT options. The position of a VRTX can also be constructed. Refer to Point and Line Construction for further information. If a VRTX is made coincident with the drafting point of another 2D primitive then a logical connection is established and the DRAG command affects the VRTX and the other 2D primitive.

The TO option defines the position of the VRTX without affecting the bulge factor and is thus similar to the standard DEF command. The CLOSE option positions the current VRTX to be coincident with the first VRTX of the OUTL and thus closes the Outline. Subsequent VRTXs can be created.

The BY and DRAG BY options move the VRTXs at the start and finish of the span by the specified amount - bulge factor and curvature are unaffected. The THROUGH, RADIUS and ASUB options only define the bulge factor - knowledge of the through point, radius and angle subtended are lost. They do not change the position of VRTXs, only the curvature of the span.

The RADIUS option can have a negative value - this results in a negative BULG and hence a span drawn in a clockwise direction. If the radius specified is not large enough to define the curvature of the span between two VRTXs then the command is ignored and a warning message output, giving the minimum possible radius. By default the command gives the minor arc, the major arc being given by

SPAN RADius value MAJor

The command SPAN @ (or NEW VRTX SPAN @) gives a simplified way of defining the span. By default, you must define the TO position by a cursor hit, a straight-line span being assumed. The Outline Span Construction window displays, giving you various span definition options.