I've been trying to find a great way to do magnetic cape clips since UD Replicas announced their TDK suits way back when. Admittedly this way only really works for their new Begins line but I am excited about how slick it is nonetheless.
I obviously don't have my UD Replicas jacket yet so I had to improvise.
This one is real heavy and has 2 layers of leather at the cape connection points. Doubt UD's will be this heavy but either way here is what I started with.
Then I would take a couple 1 inch rare earth magnets and attach them to the inside of the coat where you want the clips to sit on the front side. This could be done with glue, stitched in, or just simple tape like I have used here. Nice thing about these magnets is if you stack a couple together the hold becomes exponentially stronger. I'm gonna include one for each side with my capes but you could always add more if you feel you need it.
Then you take the female threaded magnet and pop it onto the front of the jacket. Don't worry it will only go to one place and will do so rather quickly when you get close. You have to be very very very careful of your fingers with these magnets. These ones can hold a 40 pound weight. Hurts when they snap together and your digits are in the way. Magnets can also break if they snap together hard.
Now you would feed your cowl and cape onto the pegs. I only did a cape here and as you can see it hides most of the magnet. The clips themselves hide the rest. But one could always paint the magnet black if this is a concern.
Then you take the cape clip with the male bolt already installed and thread it into the female magnet. Excuse the roughness of these clips. They are a flawed set I just use for prototyping.
Get them into the proper position and voila!
It is a strong hold especially with how light this cape is. Like I said above you could stack more magnets for a stronger hold though. Real nice thing about them though is if someone was stepping on your cape or you got it snagged the magnets will give way before the cape or leather would tear if using the more traditional bolt method.