Using repetitive size dimensions

Repetitive Size dimensions let you control the size and tolerance values for a group of objects based on a single dimension. You should use repetitive size dimensions for independent features that are dimensioned with the same nominal and tolerance values.

You can use Repetitive Size dimensions for circles, lines, and arcs. (See Placing Repetitive Size dimensions.) Repetitive size dimensions must be applied to circles that will be used in hole pattern constraints.

Note: Repetitive Size dimensions cannot be applied to Line-to-Line or Rectangular FOS dimensions as of Enventive v4.1.4, because they were found to produce inaccurate worst case and statistical tolerance analysis results.

If you attempt to do tolerance analysis on models created prior to v4.1.4 that contain Repetitive Size Line-to-Line or Rectangular FOS dimensions, a warning message will display that lists these occurrences. Please see the FAQ for more information.

Repetitive dimension callouts use the form nX, where “n” is a variable that refers to the number of objects or spaces to which the dimension applies. For example, if you use repetitive dimensioning to size six holes in a bolt pattern, where each hole has a 1.000 diameter and a tolerance of ± 0.005, the dimension callout will appear in the sketch as 6X Ø1.000 ± 0.005.

Selecting unlike object types

Repetitive size dimensions apply only to like objects. That is, circles can be associated only with circles, lines with lines, and arcs with arcs. If the selection contains unlike object types (as may occur when window-selecting objects), the repetitive size dimension will be applied only to one object type using the following criteria:

Greatest number of like objects. For example, if the selection contains three circles and four lines, the lines will be dimensioned. If the selection contains four lines and five arcs, the arcs will be dimensioned.
Object type. If an equal number of multiple object types are selected, the dimension is applied based on object type. The priority for placing the dimension is (1) circles, (2) lines, and (3) arcs. Only one object type is dimensioned; the other objects in the selection are ignored. For example, if the selection contains five circles and five lines, only the circles will be dimensioned. If the selection contains four lines and four arcs, only the lines will be dimensioned.

Selecting objects with existing size dimensions

Only one object in the selection group may have an existing size dimension, which is used to set the size of the other objects in the repetitive dimension group. If there is more than one existing size dimension, an error message will appear and you will be unable to place the repetitive size dimension until you remove the existing size dimensions.

If you have to remove existing size dimensions to place the repetitive dimension, first check whether those dimensions are being used in equations. If so, note which equations use the dimensions so you can modify them to use the new repetitive size dimension after it is placed.

If none of the objects in a repetitive dimension selection group has an existing size dimension, the average size of all the selected objects is used to determine the size.

Note: Be aware that Repetitive Size dimensions and Length Equal constraints behave differently when running tolerance analysis, so these features are not interchangeable. Specifically:

The Repetitive Size dimension assumes that the driven features are independent and are all specified using the same nominal and tolerance values.
The Length Equal constraint assumes that the driven features are interrelated and do not vary independently.