Tracing and enlarging flat patterns; copying three-dimensional patterns
To make an exact-size reproduction of a flat pattern, first trace the pattern. Then position the tracing with a sheet of carbon paper over the new surface, and retrace the lines, using a hard pencil, a ballpoint pen, or (on wood and other rough surfaces) a dressmaker’s tracing wheel.
If you wish to enlarge a pattern, draw a grid of uniform squares over the original tracing; then draw a proportionally larger grid onto the new surface, dividing it into the same number of squares. Copy the pattern by hand from the original onto the new surface, using the relationships of the squares to the pattern lines as a guide. For very precise work, add diagonal lines to all or part of each grid, further subdividing the squares.
To copy a three-dimensional pattern or some other pattern you cannot trace, such as the contours of a wall on which you want to fit a cabinet, first place the new surface at a right angle to the original. Set the point of a compass on the original and the compass’ pencil point on the equivalent part of the new surface. Draw the compass along both surfaces so that the point of the compass follows the edge of the original, and the pencil point draws its contour onto the new surface.
Another way to copy a three-dimensional pattern is to make a template by pressing a profile gauge against the surface you want to copy. A profile gauge is an assembly of tightly packed needles that draw back when pressed against a surface, taking on its shape.