I too am frustrated with i-mates. I am modeling a frame with 4 unique legs which I label LF, RF, LR and RR, relating to their position Left, Right, Front and Rear. Each leg has 3 i-mates which are all Mate half-constraints and have unique names. I also created a "skeleton" part which has 12 i-mates, with names to match each of the 3 i-mates in my 4 legs. Again, all 12 i-mates have unique names. My hope was that I could create an assembly with the first grounded part being the "skeleton" part, then each leg would "auto-Mate" upon insertion with the uniquely named i-mates shared between them. Sounds simple (and logical) enough, but such is not the case. Apparently i-mates don't care about names, unique or not. My desire in this is to emulate the behavior of the Frame Generator, allowing me to change legs while maintaining certain positional relationships between them. For instance, one set of legs might be formed sheetmetal angles 3" x 3", and another set might be 5" x 5" formed angle. These are custom forms and not something dragged in from Content Center, but I want certain faces to maintain position relative to one another. It makes want to put on my pirate eye-patch and walk around saying "Arrrrrrrrgh, hang 'em from the yardarm"!