How to Build a LEGO Castle on the Computer

Download and install the LEGO Digital Designer software (see References). If you have a preferred LEGO-themed designer program, feel free to use that instead.

Begin brainstorming your castle design. Make notes on the features you want to include, the size and shape. You may want to diagram the castle on a sheet of paper for a clearer image of how it will eventually look.

Open the Digital Designer software and start a new project.

Select a base plate for your design and place that on the field. If you are making a large design, you may want to use three or four base plates so you have plenty of room to build.

Select some large, solid bricks and begin placing the foundation layer of the building. The bottom of the structure should be large enough to accommodate the rest of the castle. It's a good idea to place the first row of columns or interior walls as well, because if you build the structure in reality and it's too large, it may collapse.

Place the next row of the structure. Make sure the second row of bricks overlaps the joints between the bricks below, so the upper row is offset from the lower. This not only makes your structure stronger, but also gives it a more realistic look, as real castle brickwork is also offset like this.

Repeat step 6 until you have completed the wall. If you have a window or door to add, leave a void in the wall there.

Build a ceiling for the first floor (or a floor for the second) using a series of large plates. You will find them in the brick palette, grouped with other plate-shaped pieces.

Add the next level. If you're adding a second floor or tower, repeat steps 5 through 8 for these pieces, otherwise you can install the battlements on the roof.

Look through the brick palette for any finishing touches. If you want to add some flags or a cannon, you'll find them and numerous other pieces grouped with similar pieces on the palette. There is even a tool for adding LEGO Minifigs, so your castle can be well-guarded by a team of knights.