I have worked on Merrell footwear at two different consultancies, JDK and Design Metro.
While at Design Metro I worked on the designs of numerous outsoles, sandal top sheets, and shoe uppers. This is a selection of these designs.
Outsoles are a fun mix of technical requirements and aesthetics. The conditions the outsole will be worn in determine whether you need siping to shed water, a special formulation for walking on icy sidewalks, bobs to shed mud or snow, deep treads for grip in loose conditions, shallow tread with lots of flat areas for grip on smooth surfaces, cleats on the edges or treads specifically shaped for lateral movement. Each little tread is a sculpture by itself and the design of the entire tread pattern must also be pleasing. For these outsoles, mountain bike tires were a big inspiration. The end result is important enough that Merrell featured some of these outsoles on their website.