12 - Select the door's top segment and press Delete to get rid of this segment.
13 - Make sure your entire spline is still selected and go the Shape tab and select a circle. Again, make sure "Start new shape" box is unselected (pict03.jpg). Now, place the cursor in the middle of the door between the two top vertices, wait till the blue box comes on and draw a nice and fat circle like in pict13.jpg. Once it's done, go back to the Edit panel..
14 - You still should be in Segment mode, so just select the two lower segments of the circle and press Delete. You should see the same just like in the picture below.
15 - Now got to the Selection menu (in the Edit panel) and switch to Vertex mode.
16 - We're going to weld some vertices, because the partly deleted door and circle's segments must be continuous. If it weren't a continuous spline, no door would show up in the final work.
17 - With the selection tool select both vertices: the doors and the circle's.
it looks like you have only one, but that's actually too, sitting on top of each other. Go and scroll down in the Edit panel until you find Geometry and within that - Weld. I normally pump it up to about 200, or higher. Don't ask me why, I just crank it up, so my welding won't fall apart. And now click the Weld box. Do it both ends of the circle. These are the vertices that will connect the half circle and the door to each other.
17 - We're almost there. Go to the Modeling panel and drop an Extrude modifier on your spline. And this is it, you've completed a wall with some windows and a door. Now click the "Maximize viewport toggle" in the lower right corner of your entire 3dsmax desktop and see all 4 viewports at the same time. This is what you should see, like in the image below.
I know it doesn't look much like a house, but if you've followed the tutorial carefully, you'll be able to build your own, much better looking house. Spline modeling is very powerful, especially for those that understand how things will change once you start converting Corner vertices to smooth, or Bezier. Take your time and try your own things out, any 2D shape can be converted to spline and that's where things can go really crazy. With this method you will be able to model countless things and very fast. It works much better than 3dsmax's boolean operations. This is how I modeled the walls, the cart wheels and those stones around the windows. In this tutorial I kept it simple, anyone can follow it, step-by-step, even if this is the first time you're using 3dsmax. Well, just about.