There are lots of ways to make realistic buildings. You can use decals that you create yourself or from freemodels to get patterns like wood or marble tiled floors, Roof shingles or whole building sides.
By using parts Set to custom formfactor and meshes, you can make really thin lines. This allows you to make real looking details.
Search for blueprints online to get ideas for buildings. Try the scale 1 inch = 0.1 stud.
Be creative, It doesn't have to look real if you don't want it too. |