Bodypart images or body-scapes per definition is fully nude, but only parts of the body will be in the pictures. Often the model is anonymous which for some models make a difference as opposed to fully nude people where both face and nude body can be seen. As with other images a lot of emphasis is made on lighting and composition/lines, and ofter images include a closer look of the private parts.
I do some work in this category, images can be very rewarding and model will (can) generally remain anonymous. It can be a good point of entry if a model want to try art-nudes but are worried about what others will think.