AutoCAD 2008 offers new and enhanced dimensioning functionality, which includes automatic alignment options, dimension breaks, jogged dimensions, text placement, and tolerances. The new Dimension panel on the Dashboard provides easy access to the many dimensioning tools.
The new Dimension Break tool (DIMBREAK command) enables you to break dimension or extension lines where they intersect geometric objects or other dimensions. After specifying the dimension that you want to break, you can select intersecting objects to use as cutting edges or you can choose the Auto or Manual options. When you break a dimension by selecting objects or using the Auto option, the breaks will automatically update when the intersection point moves. If the objects are moved so that they no longer intersect, the break will disappear and if they are moved back the break will automatically return to the proper location. The Manual option enables you to specify start and end point of the break. You can use the Restore option to remove all the breaks from selected dimensions or leaders.
A new Inspection Dimension tool (DIMINSPECT command) enables you to create inspection dimensions, typically used to indicate critical operating tolerances, from existing dimension objects. You can add or remove inspection dimensions and control their appearance including the shape, label and inspection rate. After you convert a dimension to an inspection dimension, you can edit the inspection dimension properties using the Inspection Dimensions dialog box or the Properties window.
You can add a jog to linear dimensions to represent measurements whose values are not the same length as the dimension line. Jogged dimension lines are typically used when a sheet is too small to display the true length of a dimension line. Using the Dimension Jog tool (DIMJOGLINE command), you can select the dimension and indicate where you want to place the jog. You can edit the jog location using grips and you can turn off the jog or edit its height using the Properties window. Additionally, a new option for linear jog size is included on the Symbols and Arrows tab of the Dimension Style dialog box.
The new Dimension Space tool (DIMSPACE command) enables you to evenly space selected dimensions. You can specify the spacing distance between dimension lines or let AutoCAD automatically determine a minimum spacing distance.
Enhancements to diametric, radial, and jogged radial dimensions enable you to dimension an arc beyond its endpoints. The process for creating these dimensions hasn’t changed. However, when you specify the location of the dimension line, you can drag beyond the endpoints of the arc. AutoCAD will automatically create an arc extension line using the same properties, such as extension line color and extension line offset, as traditional extension lines.
A new option for angular dimensions enables you to place the dimension text outside of the angle being measured. You can access the new option, Quadrant, from the right-click menu when prompted to specify the dimension arc line location. The Quadrant option asks you to specify the quadrant (angle) that you want to dimension separate from specifying the dimension arc line location. If the dimension arc line location that you specify is outside of the quadrant that is being measured, AutoCAD will automatically create an arc extension line to the dimension text.
And finally, the Tolerances tab of the Dimension Style dialog box has been updated to include controls for aligning tolerances. You can align stacked tolerances using either the decimal separator or the operation symbol.