Quote - Could Renderosity post a schematic of a butt cheek in its FAQ with a line mapped to establish the officially ‘normal’ bikini cut beyond which nudity is achieved? Until the element of subjectivity is eradicated, I don’t understand the hard line that moderators draw when it comes to invalid nudity and violence tags. 

There has been one up all along

http://www.renderosity.com/news.php?viewStory=13431

However, they have relaxed on the top part of the bikini.  Breast tissue can be shown, just not the areola or nipple.  Even a few pixels of areola or nipple are in violation.  Pasties are considered clothing. so make sure that if you use them that the pasties cover that whole area.   

So based on the above picture, if your figure was wearing a thong pantie and had their back or most of their back towards the camera, that would be considered nudity because the panty doesn't cover the butt cheeks.

A nude figure that has their arms or legs or jail cell bars hiding their nude parts is still considered nude.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi