Constructing the Basic Bodice Block
Added Feb 22, 2009
Now draw an line orthogonal to the line 0-B at B, across the page nearly to the other edge, and measure off half the BUST measurement plus 5 cm (or 2"). Mark this point (C). The orthogonal line may be drawn using a square, but you may also measure the distance from the top of the sheet to the point B along the line OB, and slide this measurement along the top of the page to another point some distance from the first line, and mark a new point. Then align the ruler along the two points and draw across.
A word about precision here - the more precise your work, the better the fit in the final garment. Some round-off errors are inevitable, but you should try to be as accurate as possible, to 0.1 cm or than about half a 0.1" increment. The distances sound tiny, but you are only working on half the garment, so the actual errors are doubled, and in some cases multiplied even more. Also, errors tend to accumulate, rather than cancel themselves out, in this kind of process. If you make an error of 0.2 cm once, then a second error, then a third, you are now carrying more than a cm of error in the final garment. These errors accumulate quickly and will slew the results substantially.