I have to agree with a lot of you that nudity must have a reason to be in the story to be present. In my own writing I often have scenes with nudity, but, with few exceptions, it's not sexual in nature. It's usually anthropological. In other words, I have many cultures within the world and each of them have different societal norms. Among some, nudity in front of others is frowned on in every context. In others, nudity is fine in the context of bathing or swimming, but some segregate this by gender while others don't see the need. Still others may see male nudity as normal in certain contexts, even with females present, even while complete female nudity is seen as improper when males are around.
Within scenes where it's a normal aspect of society, it just IS, and nobody reacts to it or comments on it. It only becomes part of the commentary when there are individuals from two different cultures who are interacting and have a misunderstanding. For example: In one of my novels I have a male and female wood elf from two different tribes traveling together. She suggests they go swimming, tosses her upper garment and shoes to the side, and leaps into the water. She is then surprised and embarrassed when the male wood elf tosses his clothing aside and jumps into the water naked. He was not surprised by her attire (a loincloth and chest wrap), since females in his tribe tend to wear something similar when swimming. She is surprised by his complete lack of clothing because in her tribe males wear at least a loincloth when swimming in mixed gender settings. Once the initial discomfort is past due to the misunderstanding, this then sparks a conversation since they realize there's so much about each other's respective tribes they didn't know. They had both assumed they were more similar, both being wood elves, but the situation leads to them realizing there were still a lot of differences, and this leads to them having continued conversations as the book progresses in which they learn more about each other.
