CAD > Insert > Dimension

A dimension is a model entity which is used to indicate various measured values of model entities.

All dimension entities are associative. If the model is changed, the dimension entity describing that part of the model is automatically updated. All dimensions are placed in one view only, the dimension is inserted in the view where the first location point is specified.

All dimensions are inserted relative to the currently active construction plane (CPL). A dimension entity usually consists of a combination of a value, prefix text, suffix text, line terminators, projection lines and leader lines. The dimension entity may be in the form of a linear, angular, radial, diameter or area dimension. Dimensions can be inserted without accompanying values. A dimension entity can be inserted with its value subject to several tolerance methods. These are Dual, Upper-Lower and Plus-Minus.

Angular dimension values may be specified in decimal or degrees:minutes:seconds notation. The actual values of dimension entities may be scaled to indicate other units of measurement. Entities are measured in model units, usually representing millimetres. The dimension entities are drawn to meet the requirements of the Australian Standards, AS1100 Parts 1 to 13. A dimension value can be inserted with standard or user specified prefix and/or suffix text, which can be subsequently edited.

Dimension value-text may be moved. All dimension value-text is assigned the option Plot Size /Plot Scale (i.e. the dimension values will always be plotted at the height specified, irrespective of the plot scale). Also, the weight for the value-text is always proportional to the text height assigned to the dimension entity. The terminator of the dimension lines can be selected from arrows (open or solid), dots (open or solid) and slashes. The length (or diameter) and height values of the terminators can be specified.

A dimension entity may have its terminators placed inside or outside the projection lines.

The gap, length and extension values of the projection lines of a dimension entity can be specified. Any projection line can also be visually removed.

Dimension Insert
The Dimension Insert command enables the Dimension Insert menu allowing the insertion of various types of dimension entities.

The types of dimension entities are:

• Value Only
• Horizontal
• Vertical
• Parallel
• Linear
• Common-Horizontal
• Common-Vertical
• Common-Parallel
• Parallel Line
• Common Points
• Horizontal Ordinate
• Vertical Ordinate
• Angular
• Angular Lines
• Leader
• Component Leader
• Multi-Lined Leader
• External Radial
• Internal Radial
• Diameter
• External Diametric Internal Diametric
• Distance
• Bearing
• Area.

Not all these options are available from the Pulldown Menu. For the rest of the options, turn on the right hand menu [Menu On/Off] and go to CAD > Dimension. The dimension entity is not only inserted subject to the method of insertion but also the specified default options.

Hor
Allows the insertion of a linear dimension entity whose dimension lines are parallel to the x-axis of the currently active CPL (i.e. the dimension lines are horizontal). The dimension value entity is the difference of the x-axis coordinates of the two selected dimension point locations. The location of the dimension line relative to the x-axis is selected first followed by the two or more location points being dimensioned. If Dimension Defaults Tolerance is not set to None and the Tol Entry is set to Manual, the upper and lower tolerance range values are specified and must include the required polarity.

If more than two point locations are selected, the value of the dimension entity is the difference of the x-axis co-ordinates of adjacent points. The dimension entity will lie on the currently active CPL. The value will be centrally placed between the projection lines.

Ver
Allows the insertion of a linear dimension whose dimension lines are parallel to the y-axis of the currently active CPL (i.e. the dimension lines are vertical). The value of the dimension entity is the difference of the Y co-ordinates of the selected point locations being dimensioned. The location of the dimension line relative to the y-axis is selected first followed by the two or more location points being dimensioned. If Dimension Defaults Tolerance is not set to None and the Tol Entry is set to Manual, the upper and lower tolerance range values are specified and must include the required polarity.

If more than two point locations are selected, the value of the dimension entity is the difference of the y-axis co-ordinates of adjacent points. The dimension entity will lie on the currently active CPL.  The value will be centrally placed between the projection lines.

Par
Allows the insertion of a linear dimension entity where dimension lines are parallel to an existing line entity. The line entity is selected first followed by the desired location point for the dimension line relative to that selected line entity. Next, the two or more point locations to be dimensioned are selected. If Dimension Defaults Tolerance is not set to None and the Tol Entry is set to Manual, the upper and lower tolerance range values are specified and must include the required polarity.

If more than two point locations are selected, the value of the dimension entity is the distance between the adjacent points projected on the line from the selected points. The dimension entity will lie on the currently active CPL. The value will be centrally placed between the projection lines.

Diameter
Allows the insertion of a diameter dimension entity describing the value of a diameter of a selected circle entity. The dimension line is inserted inside the circle entity, passing through the centre. Two terminators appear at the intersection points of the dimension line with the circle entity circumference indicating the diameter of the circle.

The circle entity is selected first. Next, the leader corner is selected followed by the approximate end of the leader is selected. If Dimension Defaults Tolerance is not set to None and the Tol Entry is set to Manual, the upper and lower tolerance range values are specified and must include the polarity.

The circle / arc entity must lie parallel to the current active CPL. The diameter dimension entity lies on the currently active CPL.

Area
Allows the insertion of a dimension that displays the area of a plane entity. The desired point location of the area value is selected first, followed by the plane entity to dimension.

The value of the dimension entity lies on the currently active CPL with the base of the value parallel to the x-axis.