External References
When fitting and positioning parts during construction, reference is frequently made to other construction objects, e.g. if you insert a hole relative to the centre of a hole in another part. This reference between two parts is called external reference.
Example:
When inserting the hole in part 2, the centre of the countersink of part 1 is defined as an external reference. If this reference part changes its position, the hole will also change position so that the defined distance remains the same.
External reference between two parts
If you want to prevent such reference, deactivate the 
Use external references function.
In addition to the setting for the body, specifying whether external references are to be used generally, you can define for individual feature elements whether these are to use external references or not (even contrary to the body setting if desired). If the Body setting option has been set, the external references-related behaviour for the body will always be adopted in the feature.
An example: Let us assume that you want to copy trimmed Steel Engineering beams, and want to preserve the reference to the beam to which the trimming is applied in some of the cases (if the copied beam will also be trimmed to the same beam), but not in the other cases (if the beam is to be copied to another position).
You can then preserve the external reference on the body while copying, but deactivate it for individual beams in the feature parameter. For the intersecting edge in the feature log, the utilisation of the external reference can be suppressed if the body setting is different.
Intersecting edge > External references in processings 
When a feature uses a sketch, the feature log shows at the sketch entry's icon whether the sketch contains external references and whether they are used:
-
symbolizes a sketch with external references that were actually used. -
symbolizes a sketch that contains external references that were not used, for example, because the use of external references was deactivated.
Please note:
- External references are indicated by special icons in the feature log.
- If you copy a Design Variant not completely, i.e. if you omit some of its parts, the omitted parts will be deleted from the list of the associated parts and will be highlighted accordingly in the graphic. Start scripts will be removed and, as a result, all calculated local variables will no longer be changed. All feature parameters of the original Design Variant will be treated like normal features; in particular, all placements of parts referring to omitted parts will be removed.
