Clandestino, you are trying to be sarcastic but you are not providing any answer for help.
"Generic RCW"? "if you have no obstacles"? FSX?
Why you assume NG?
Its a generic question, goes for all runways, short-long, obstacles or not. You can do reduced N! on all with approved runway analysis data.
Can you do it without?
Personal opinions and not supported reasoning does not help.
Keep the jokes for your FSX buddies and RTFQ. Its not about actually taking off or not.