In SOLIDWORKS, there are times when you are modifying an existing part and that part has external references. External references can be created when you add relations from one part to another. For instance, you have a box or housing and you want to create a cover that will match the size of the housing and be connected to it. So if the housing changes, the cover will automatically be changed to match it. By adding these relationships it creates external references. Well how do you see those relationships in a sketch? Let's take a look at this jaw plate.
First thing you notice is there is a symbol next to the feature that has external references.
You can also right click on the feature itself and select "List External Refs…"
As you can see, there are a lot of ways to get the same results in SOLIDWORKS. What if you want to see the external references while you are in the sketch? All you have to do is select Display/Delete Relations while in a sketch.
Once you are in the Display/Delete Relations command, you can sort to only show you the external references.
Now all of the external references are showing in the sketch and you have the ability to change or delete as you see fit. For more information about external references, please check out the SOLIDWORKS help for all the options you have with them.
Field Technical Services Manager