Creating and Manipulating Drafting Primitives - Specific Operations

This section describes primitive-specific operations. If an operation is not specified then it is ‘universal’ (that means, applies to all primitives and as such is described in the previous section) or it is similar to the same operation as described for the CIRCLE primitive see CIRCLE (CIRC) below.

ARC (ARC)

Attributes

Basic Creation Method

An ARC can be defined in three ways:

• by defining the positions of the end-points and a ‘through’ point (from which the values of Radius (RADI) and Angle Subtended (ASUB) can be derived if required).

• by defining the position of the center point, ‘from’ point and Angle Subtended (from which the position of the ‘to’ points and the value of RADI can be derived if required).

• by defining the position of the center point and two end points.

The method:

NEW ARC

DEF @

results in three points being prompted for (the ‘start’, ‘end’ and ‘through’ points). A line is drawn through the points and TCOD is set to ENDPOINT. See Positioning (absolute) overleaf for the second method. If used with an existing ARC any existing values of RADI and ASUB are altered accordingly.

Defining or redefining an Arc with a centre- and two endpoints is achieved using the command:

ADEFine <dfnpt> <dfnpt> <dfnpt>

where <dfnpt> defines a position (2D, 3D, p-point etc).

The first two points are the centre - (CPT) and ‘from’ point (FPT) of the Arc. These two points define the radius. The third point defines the angle subtended by the arc. The TO-point (TPT) lies in this direction from the Centre (CPT) at the same distance as the FPT from the CPT. The TCOD attribute is set to CENTRE.

This command may also be used with the cursor:

ADEFine @

A prompt requests three 2D points to be input for CPT, FPT and angle subtended. 3D points may also be input using the cursor:

ADEFine ID@ ID@ ID@

DEFine IDP@ IDP@ IDP@

Changing Radius and Angle Subtended

RADIUS value [Design]

Sets RADI. For TCOD CENT this moves the ‘from’ and ‘to’ points radially (by the change in the value of the radius). Centre point position and ASUB are not altered. For TCOD ENDP this moves the ‘through’ point and changes ASUB; the positions of ‘from’ and ‘to’ points are unchanged.

RADIUS X value Y value

RADIUS E value N value U value

RADIUS IDP @

For TCOD ENDP this is like THPT @.

ASUBTENDED value [ANTICLOCKWISE]

ASUBTENDED value CLOCKWISE

Sets ASUB. (A positive angle is anticlockwise, a negative one clockwise.)

For TCOD ENDP this repositions the ‘through’ point (mid-way along the Arc) and changes RADI; ‘from’ and ‘to’ point positions are unaltered. For TCOD CENT this moves the ‘to’ point of the arc. Centre and ‘from’ points and radius are unchanged.

ASUBTENDED CLOCKWISE

ASUBTENDED ANTICLOCKWISE

Sets the value of ASUB to be negative or positive, respectively.

ASUBTENDED @

For TCOD ENDP this is like THPT @; For TCOD CENT this alters the angle subtended and hence moves the ‘to’ point of the Arc. The new position of the ‘to’ point lies on the line joining the centre-point and the cursor position; centre and ‘from’ points and radius are unaltered.

Positioning (absolute) (of an arc point)

The syntax is similar to that for FPTs of STRAs. Possible points are CPT (centre point), FPT (‘from’ point), TPT (‘to’ point) and THPT (‘through’ point).

CPT @

This changes the arc to be one with TCOD CENT (if not already so). The Centre is moved whilst keeping the ‘from’ point and ASUB unaltered. The ‘to’-point and radius are recalculated.

THPT @

This changes the Arc to be one with TCOD ENDP (if not already so). The position of the ‘through’ point is moved whilst keeping the ‘from’ and ‘to’ points fixed - that means, both radius and angle subtended are altered.

FPT @

TPT @

For arcs with TCOD ENDP, the ‘from’ or ‘to’ point of the Arc (as appropriate) is moved whilst maintaining the positions of the other end point and the ‘through’ point.

For Arcs with TCOD CENTRE, the ‘from’ or ‘to’ point of the Arc (as appropriate) is moved whilst maintaining the position of the centre and the angle subtended. Thus the radius may change and the position of the other end point will be moved to preserve the angle subtended.

Repeated Copying

See Circles.

Querying

Similar to Straights, but referring to RADIUS, ASUBTENDED, CPT, FPT, TPT and THPT as appropriate. The Q IDN @ command may also be used

Dragging another primitive to which the Arc is connected

During the course of a DRAG operation on another primitive, the points of the Arc may move. The effect on the Arc is as follows.

• for arcs with TCOD ENDP, Radius and Angle subtended are changed.

• for Arcs with TCOD CENT, if the centre point is dragged, then the positions of the ‘from’ and ‘to’ points are also moved to preserve the Arc’s appearance.

• For Arcs with TCOD CENT, if an end point is dragged, then a rotation about the other endpoint takes place, that means, the centre point is moved and the radius changed.

CIRCLE (CIRC)

Attributes

Basic Creation Method

NEW CIRCLE DEF X value Y value X value Y value

(‘manual’ method of NEW CIRCLE DEF @ command described in section 14.4.1. This method applies to all primitives described below, except where otherwise specified.)

Note: If used with an existing Circle the DEF command always sets ADEG=0 and ORIG=CENTRE

Identification

ID CIRC @

This method applies to all primitives described below, for example ID ELLI @ (ellipse), ID RECT @ (rectangle)

Resizing

DIAMETER value [DESIGN]

RADIUS value [DESIGN]

If Design specified and if underneath a VIEW from which a scale can be obtained, a scaled circle will be drawn and the diameter stored in the database as a Design value.

DIAM @

Sets DIAM equal to the distance between the two points, ADEG equal to the angle to this line from X axis; if ORIG is CIRCUMFERENCE, origin is positioned at the first hit.

DIAM X value Y value X value Y value

Manual method

Redefining the Origin

ORIGIN @

Prompts:

Select a possible origin of the CIRC

ORIG CENTRE

Sets ORIG as required and changes position of origin to point specified. The Circle itself does not move.

ORIG CIRCUMFERENCE

Positioning (absolute)

ORIG X value Y value

ORIG CENTRE @

ORIG CIRCUMFERENCE @

ORIG IDP @

ORIG POS @

ORIG ID @

ORIG IDDP @

The last option (ORIG IDDP @) places the primitive on the drafting point used by another primitive and hence ensures connectivity for the DRAG command.

Moving about the origin

OCOD CIRCUMFERENCE

Moves origin to circumference of Circle. See Figure 18:17 below.

Figure 18:7. Moving about the Origin - Use of the ORIG Command

Rotating about the origin

ADEGREE value

Sets ADEG as specified, causing the circle to rotate about its origin. (If this is at the centre then no visible change is seen.)

Querying

In addition to the standard attribute queries the following are provided:

Q DESC

Queries the origin, position and diameter

Q DIAM

Queries the diameter in Annotation or Design coordinates as appropriate

Q ORIG

Queries the origin and its position

Q OFFS

Queries the position relative to the NOTE origin

DIAMOND (DMND)

Attributes

Resizing

As for Ellipses.

All other operations are as for Circles.

ELLIPSE (ELLI)

Attributes

Resizing

Redefining the Origin

ORIGIN @

Sets ORIG as required and changes position of origin to point specified. The ellipse itself does not move

ORIG CENTRE

ORIG RSIDE

ORIG LSIDE

ORIG TSIDE

ORIG BSIDE

All other operations are as for Circles.

EQUILATERAL TRIANGLE (ETRI)

Attributes

Resizing

LENGTH value [DESIGN]

Sets side length

THROUGH @

THRU    @

Prompts:

Input a point on the current sheet

Sets LENG so that the triangle passes through the point specified.

This may not necessarily be a corner - ADEG will not be altered.

THR X value Y value

Manual method

FRADIUS value [DESIGN]

Sets FRAD to value specified. If this is too big for the existing value of LENG then a warning is output, the triangle is drawn sharp-cornered, but the FRAD attribute is set as specified and will be used when the LENG value is made large enough.

Redefining the Origin

ORIG @

prompts: Select a possible origin for the ETRI

ORIG APEX

ORIG BASE

ORIG LSIDE

ORIG RSIDE

ORIG BLEFT

ORIG BRIGHT

All other operations are as for Circles.

HEXAGON (HEXA)

Attributes

Redefining the Origin

As for Circles. ORIG CIRCUM refers to a vertex of the Hexagon

All other operations are as for Circles.

MARKER PRIMITIVE (MRKP)

Attributes

All other operations on Markers are similar to those for Circles (where relevant).

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. This 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 may be drawn through the vertex points of the OUTL (see CURFIT below).

Attributes

(OUTL)

Setting CURFIT to CUBICFIT will cause 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 would not normally be set explicitly, but indirectly by the SPAN command (see below).

Chamfering

A chamfer may be applied between two VRTXs using

CHAMFER value [value]

The value(s) supplied in the above syntax must be greater than or equal to 0. If two values are supplied then the first chamfer distance will correspond to the chamfer joining the current VRTX to the previous one, and the second will correspond to the chamfer joining the current VRTX to the next. If only one chamfer distance is supplied, then both chamfer distances will be 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 will be drawn straight, that means, the BULG attribute of the current and next VRTX will be ignored. CHAMFER OFF will remove the chamfer.

Filleting

A fillet may be applied to a VRTX using

FRADIUS value

Any value may be supplied in the above syntax. A positive value will correspond 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 will be drawn straight, that means, the BULG attribute of the current and next VRTX will be ignored.

VRTX Basic Creation Method

The OUTL and VRTX elements may 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. This 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. If a VRTX is made coincident with the drafting point of another 2D primitive then a logical connection will be established and the DRAG command will affect 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. This does not have to be the last VRTX though - 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 will result 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 will be 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 form will appear, giving you various span definition options. See the on-line help for further information.

Querying

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, SKEtch POInts, SKEtch ORIgins and ID @ commands are all valid at OUTLs and/or VRTXs. Note that SKETCH ORIG ALL does not sketch all VRTX origins - only the origins of the owning OUTLs - that means, the first VRTX below each OUTL.

RECTANGLE (RECT)

Attributes

Resizing

Redefining the Origin

As for ELLIPSE, but also:

ORIG TLEFT

ORIG TRIGHT

ORIG BLEFT

ORIG BRIGHT

Creating Rectangles and Squares

Rectangles can be created using the commands:

For example:

These commands may also be used with the cursor, for example:

ADEFine @

A prompt requests two 2D points to be input.

All other operations are as for Circles.

STRAIGHT (STRA)

Attributes

Basic Creation Methods

A STRA can be defined in two ways:

• By defining the positions of the end-points (from which the values of length and angle can be derived if required).

• By defining the position of the mid-point and values of LENG and ADEG (from which the positions of the end-points can be derived if required).

The commands:

NEW STRA

DEF @

results in two points being prompted for; a line is drawn between the two points and TCOD is set to ENDPOINT. See the section on Positioning (absolute) below for the second method.

The command:

ODEF @

prompts for two points. The straight will be vertical or horizontal depending on the relative sizes of the horizontal and vertical offsets between the two points given.

Changing Length or Slope

Positioning (absolute)

A STRA may have its ‘from’ point, ‘mid’ point or ‘to’ point positioned or moved. Apart from the initial keyword (FPT, MPT, TPT) specifying which point you are setting the syntax is similar throughout, as the following examples show::

If the MPT command is used, the TCOD will be set to MIDPOINT. This is a single point STRAIGHT and must have its LENGTH set.

A straight can also be created by giving an orthogonal To point:

OPPT x 50 y 97

OTPT @

The straight will be vertical or horizontal depending on the relative sizes of the horizontal and vertical offsets between the From point and the To point.

Points on a STRA (FPT, TPT etc) may be identified using the command:

Q IDN @

Positioning (relative)

It is possible to move a STRA or one of its points by a given amount. For a single point STRA (that means, one with a mid-point) there will be no difference between moving the STRA itself or its mid-point, but for a two point STRA moving its ‘from’ or ‘to’ point will cause its length and/or its slope to change; the position of the other point will remain unchanged.

depending upon whether the STRA is currently positioned on a 2D point or a 3D/p-point.

depending upon whether the point is currently positioned on a 2D point or 3D/p-point.

Repeated Copying

See Circles.

Querying

Q DESC

queries the Length and point attributes, that means,

LENGTH value

ADEG value

FPT X value Y value

TPT X value Y value

Q FPT

Queries the position of the 'from' point if set. Similarly for TPT, MPT

Q OFFS

Queries the offset positions of the points set (relative to the Note origin)

Q FPT OFFS

Queries the offset of the 'from' point relative to the Note origin (similarly for TPT, MPT)

SKETCH POINTS

Sketches all points currently in use for the STRA

SKETCH FPT

Sketches the ‘from’ point (if set) - similarly for the TPT and MPT

SKETCH ORIG

Sketches first node

SKETCH POINTS ALL

At NOTE level, displays all the points currently in use for all member primitives

SYMBOL INSTANCE (SYMB)

Attributes

When instancing a symbol (SYMB), the TMRF attribute should reference a symbol template (SYTM) in the symbol library (SYLB). If this attribute is not set, nothing will be drawn.

Changing Size and Orientation

You are requested to input two points; the first point selects a position on the symbol, the second point sets a new position for the selected point. The new symbol size is calculated from the ratio of the distances of those two points from the symbol origin.

All other operations are as for Circles.

Updating Symbol Instances

The command

UPDATE INSTANCES

valid at SHEE, BACK, OVER, SYLB, LALB or above, scans the database hierarchy and updates all those parts of picture files that use the graphics instancing mechanism. For example, a SYMB is an ‘instance’ of a SYTM. OLAY and BACK elements are in the same category.

TABLE (TABL)

Attributes

All operations, including definition using the ADEFine, ASDEFine and SDEFine commands, are similar to those for Rectangles, except that FRAD does not apply. Internal rows and columns are drawn using NLSTYLE/NLCOLOUR by default. If ROWSTYLE/ROWCOLOUR or COLSTYLE/COLCOLOUR are set, internal rows and columns may be drawn in a different style and colour to the outline rectangle.

TEXT PRIMITIVE (TEXP)

Attributes

Resizing

Set the CHEI, LHEI, CSPA or LSPA attributes.

Redefining the Origin

Set JUST (justification) or ALIG (alignment).

All other positioning operations are as for Circles (see CIRCLE(CIRC)).