Have painted many rooms while nude. About the only time not nude while painting is when near a window (shades removed) or door when open to the outside.
Not long ago my wife wanted me nude while painting our garage. Thought it best not to be nude because I wanted the garage doors open for the extra light it would provide and ventilation for drying.
Just painted one of my bathrooms naked and touched up walls that got hit during move in. I have to say once I'm home I'm naked. I'll even open my front door and check the mail (my mail box is at the door). I think someone has seen me once or twice. :)
My brother and I once went into an old abandoned house. There wasn't any warning signs, so it was pretty much open space for exploration. We found this jar of black paint, and he wanted to play with it. I didn't mind it because it was something to do, but neither of us wanted to get too messy. We painted a door black and in the nude, then had to stop very suddenly. It turns out that the paint was actually tar... Or that it hadn't been used in so long that the paint was no longer just paint. Despite the fact we didn't have clothes on, it still took quite some considerable time to get that stuff off our skin (more my brother than myself.)