I fully appreciate the power of being able to create custom families that are fully parametric and the versatility this would bring to a project. However, depending upon the part this can become complex. Out of interest how many people create individual family types per part size required (if anyone) e.g. one rfa file per family size that you require meaning you would have 10 rfa files, each containing an individual part size that you require for a piece of plant vs the parametric method where you would have 1 rfa file set up so that you have full parametric control over numerous part sizes that you require. I understand that you would essentially have 10 files containing the same item but at different sizes.
I am currently creating a standard library of MEP parts so am curious which method people use, or a combination of the 2 depending on the complexity of the part.
I'd say 99% of the time, it makes sense to build a parametric family, especially if the part retains the same overall shape and only grows in physical size based on the part/model number. A parametric family really doesn't take much more time to build. Even if the part varies in shape based on part/model number, there are ways to make the family parametric. Plus, if you need to make a change to a family, do you want to make that change once or ten times? On the other hand, it might not make sense to make a parametric family for a one-off/custom part that you may never use on another project.
Jason Seck BIM Specialist Henderson Engineers, Inc.