u3d ver.5.6.1 - keep on updating~( ×ω× ) -

• Simplely place buildings on the ground and check the colliders between buildings.

• Key A and key D to alter the direction of the placeable building.

Attach BuildingPlacement.cs and BuildingManager.cs to a whatever gameobject.

BuildingManager.cs manages all the buildings you wanna build in the game. All the building prefabs need rigidbody, collider, PlaceableBuilding.cs and a "Building" tag name.