Consider a rectangular PCB with four identical mounting holes. Also consider that this PCB must be mounted to a tray in an enclosure. The positions of the holes can be defined by two dimensions, something I would typically call the major and the minor hole pitch.
I think it makes sense to build a sketch consisting of construction lines and points; the points defining the hole centers. I typically would create the four holes manually and use global variables/equations in order to define/drive the hole pitches. Perhaps I should look into using the `Pattern' functionality here.
I think that making a hole center sketch library feature makes sense because the same pattern can be used on the PCB (or some other plate-like part) as on whatever part the PCB will be mounted to. For example, clearance holes could be patterned on the PCB while threads for an appropriate standoff could be patterned on the mounting plate.
I would then be tempted to either:
A) Define a library feature which is a single `through all' extruded cut representing the clearance hole for the PCB mounting holes. Then, import four of these library features at the hole centers, OR
B) If nesting of library features is implemented/a possibility, simply create a higher-level library feature, into which the hole center sketch is brought in initially, a sketch consisting of a series of circles placed at the hole center points is created, and an extruded cut is done.
I hope to have made clear what it is I would like like to accomplish. And further, I hope to have described my approach in sufficient detail that it may be obvious where some of the issues reside. I've given a specific example here, but the same problem appears over and over again, whenever you want similar patterns across different parts.
Any comments/suggestions are greatly appreciated.