[quote=@Thundercrash]
So, suppose you come up with a story setting. It has several elements that you think mesh together really well, you have character traits that you think could produce some interesting situations, and overall you think that you can make some well-thought out stories in this setting. 

Now suppose you come across a long-running book series that you have never read, or even really knew existed, but whose setting is nearly identical to what you came up with. And by identical I mean many people would think that you had simply copied this other author. 

Would you still use what you came up with, or would you scrap it entirely?
[/quote]

Hard choice. There's no such thing as an original idea to be blunt. Avatar the movie was basically pocohantas in space, yet I remember a lady got done for plagiarism of the Harry Potter books by having a similar story.

Even my last rp design where people are in the future and lost the ability to reproduce turns out to be similar to a very obscure anime. Never seen it, but I was like wow.

I suppose it comes down to how you write it. If it's very similar to the point where things are the same, then maybe twist some elements a little bit.