I made another S-Hook! There are plenty already, but this one is strong enough for winter coats with minimal material usage. the dimensions are optimized for the ikea komplement wardrobe with one or two bars and 15mm diameter. they are not parallel to the door but to the sides of the closet.
 

Update: I added the f3d FIle, which should be customizable via parameters! you can adjust:

• top diameter (should be bigger than the actual bar) 
• opening diameter (should be a little bigger than the bar, e.g. do 16mm when bar is 15 mm)
• bottom diameter
• width (if you look at and see the s shape)
• depth (if you look from the side and see an I)