Detect if the villager can build in that region?

Ok, for my new map I need a way to detect if a villager can build at the ordered region.
Does anybody know a way?

Edit: I think I found a way.

Let us know?

I run a check to see if the amount of units in the region is greater than 0.

u could also do it so when the worker enters the area its worker ability disappear... that way u can be sure he won't build any thing.

Huh? When I remove his worker ability then he can't build the house... ?!

it like an acolyte without his summon ability.. then the button will disappear.. that mean u can press any button that link u to the building rigth ?

???

the villager spawns in the map, gets a random region where he should build his house. He walks there and starts building.

doh !!! sry i missed the whole sense of ur topic... sry :/

but u can cheack through unit type... like a specific unit enters that area.. then he can/not be able to build there...

It's ok. I have only one problem..
..sometimes spawned units just stand there and don't do anything.