What are the appropriate circumstances and contexts for woman (or indeed a man) to be seen nude?

[Frumentarii]

What are the appropriate circumstances and contexts for woman (or indeed a man) to be seen nude?

Firstly in person my another person, secondly in the media and arts, and thirdly does the degree of nudity matter?

Too many to list surely! On a whole myriad of occasions, in many different contexts.

Are there degrees of nudity? I thought that nude meant not wearing anything.

I'll add breastfeeding. Most of the time, nothing is shown, when for some reason nipple/breast is flashed then that is entirely appropriate.