Check if fondation are near.

Hello everybody,

Im just new in plugin programming and i would like to do this :

- Detect if a foundation is near another fondation (paste to it)
- Detect if another foundation exit at 3 foundation of interval

Shema (Explications)

- Near foundation : Alumnisia.fr/Rust/Fondation%20near.png
- Interval foundation : Alumnisia.fr/Rust/Foundation%20interval.png (The twig is for the distance (Check interval beetween the stone foundation))

Thanks for your help.