If you would like to create 3D architecture for your own use in your 3D animations or renderings, or to sell for profit, there are many programs you can use to help you do this, including Maya, Cinema4D or 3DMax. But most of us would find these programs either too complex or too expensive. Fortunately, Google SketchUp is a simple-to-use program that can do almost everything you will need when it comes to designing basic architectural models.
Start with some preliminary sketches of what you might want to build. This is basically the brainstorming part of the process. You should draw a basic floor plan and write out the measurements on it. Now open Google SketchUp. You will see that there is a small human male standing in the scene. You can delete this, but it helps you judge relative sizes as you are building your design.
Drawing the Outline
Select the “line” tool and start drawing out the shape of the building on the ground plane. Use the guides to help you keep your line on the axis you intend. The guidelines are color green, blue and red, and will show when your line is on an axis. Once you have your outline on the ground, you can use the Push/Pull tool to raise it to the height you want. You can also judge the height that you need relative to some other object in the scene by clicking on the top of that object as you use the Push/Pull tool. A dotted line will appear between your object and the one you referenced when you are at the correct height. Use the Line tool to define areas like inner walls and holes for windows and doors. then use the “Delete” key to remove the polygons still at the doors and windows, and the “Push/Pull” toll to raise the inner walls to the correct height.
You will also probably want to add materials and colors to your models. To do so, click on the “Paint Bucket” icon. This will open a dialog with many types and categories of materials you can add to your model. Select one you want, click “OK” and then click on the area of the model you want to apply the texture to. For instance, if you want to add something to the outer wall, you might apply brick or a nice colored siding. Do this for all the parts of your model. Now just save your file and export it in the Wavefront OBJ format.