>>6870878Wouldn't call them an 'evolution', just a differently engineered type of doll.
>same proportionsSorta. They are the same scale (1/3, or ~55-60cm) as many BJDs ('SD sized' BJDs, named after Super Dollfie line by Volks.) But other sizes of BJDs exist (1/4, 40-45cm BJDs are very popular, called a 'mini' size).
But yes, DDs, Smartdolls, and SD-sized BJDs all share the same scale. (Obitsu is special case bc they also make a bunch of other sizes, but the 50cm and 60cm ones are also 1/3.)