Create Building Level like Sims

Hey guys, I’m pretty new to Unity3d (few months), so I know a good amount of basics.

So far when I create an object like a cube or sphere, its just defined by a transform. I have no way to specify that I want to do something with one face of the cube or one corner of the cube.

I want to start making prefabs like doors and windows, but I need to know how to specify the side with the ‘hinges’ so that players can piece together game objects appropriately during their gameplay like building a house in Sims, where good match is green and inappropriate match is red.

Can you guys give me the general idea of what Classes to use or whatever so I can start to research it??

I’m using a really useful add-on to manipulate walls and stuff. It helped me save lot of time. Check the 1, as for the windows and other models, you can create some models with this add-on like door frames, stairs but don’t imagine anything crazy. If you want more advanced models you should use other programs (3DS Max, Maya 3D, Blender, etc.)