OUTLINE (OUTL) and VERTEX (VRTX)

An Outline consists of a user-defined series of connected straight lines and circular arcs (collectively known as spans). OUTL elements do not have any geometry or positional data themselves, because they are of indeterminate complexity. Geometry and positional data is provided by a list of owned Vertex (VRTX) elements. The origin of an OUTL is considered to be at the position of its first VRTX. As an alternative to straight lines and circular arcs, a smooth quadratic curve can be drawn through the vertex points of the OUTL.

Attributes

OUTL

Setting CURFIT to CUBICFIT causes a smooth quadratic curve (which approximates a series of cubic curves) to be drawn through the vertex points of the OUTL. CURFIT DEFAULT turns off the curve-fit function.

VRTX

Bulge Factor

The BULG attribute is unique to the VRTX element, and is the ratio of the maximum departure of the arc from the chord joining two VRTXs to the chord half-length. It is positive when the span lies to the right of the chord when viewed in the direction VRTX1 to VRTX2, negative when it lies to the left. A straight span has a BULG of 0, a counter-clockwise semicircle a BULG of 1.0, and a clockwise semicircle a BULG of -1.0. BULG is not normally set explicitly, but indirectly by the SPAN command.

Chamfer

A chamfer can be applied between two VRTXs using

CHAMFER value [value]

The value(s) supplied in the syntax must be greater than or equal to 0. If two values are supplied then the first chamfer distance corresponds to the chamfer joining the current VRTX to the previous one, and the second corresponds to the chamfer joining the current VRTX to the next. If only one chamfer distance is supplied, then both chamfer distances are set equal. Setting the chamfer distance to 0 is equivalent to setting it to OFF. If the chamfer distance is set on a VRTX then the spans on either side of it are drawn straight, for example, the BULG attribute of the current and next VRTX is ignored. CHAMFER OFF removes the chamfer.

Fillet

A fillet can be applied to a VRTX using

FRADIUS value

Any value can be supplied in the syntax. A positive value corresponds to a convex fillet radius at the VRTX, a negative value to a concave fillet. Setting FRAD to 0 is equivalent to setting it to OFF. If the fillet radius is set on a VRTX then the spans on either side of it are drawn straight, for example, the BULG attribute of the current and next VRTX are ignored.

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 TO CLOSE

Vertex point coincident with starting vertex.

SPAN STRAIGHT TO 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. See 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.

Query

Q DESCription is valid at OUTLs and VRTXs, giving details of origin coordinates and span radius and angle subtended (if appropriate). Q SPAN RADius and Q SPAN ASUBtended are valid at VRTXs only (but not at the first VRTX in an OUTL).

Miscellaneous Commands

The Q COMmon, HIGhlight, and ID @ commands are all valid at OUTLs and/or VRTXs.