The next stage is to draw the outline of the building (the roof line, gable ends, corners, windows and doors). This also needs to be done in your drawing software, using guidelines as necessary, and exported as a 600dpi, 24 bit colour bitmap drawing. Figure 2a shows the outline of a small mess hut.
Most buildings are sized to avoid unnecessarily cutting too many bricks, so the building dimensions are dependent on the bond used. Buildings using stretcher bond are generally in multiples of whole bricks (i.e. multiples of 3mm in 4mm scale). English bond structures are generally in multiples of whole bricks, plus one half brick (i.e. multiples of 3mm plus 1.5mm). Flemish bond should be in multiples of one and a half bricks, plus one whole brick (i.e. multiples of 4.5mm plus 3mm). Spacing between door and window openings may follow the same rules, but some cutting of bricks is sometimes necessary, so if you're very picky you may want to play around with more detailed patterns.
The reasons for the rather odd multiples will hopefully become clearer when the finished building is drawn out, and the corner detail added. Have a look at the real thing if you're not sure.
The mess hut uses Flemish bond, and is 57 by 48mm.
Figure 2a shows the outline. You may not be able to see all the lines - click on the image for a larger view. If you still can't see all the lines, enlarge the new window to full screen.