Structural Design
In all structural design similar drawings are necessary, although sketch designs in perspective may be made to suggest effect, working drawings are imperative to the execution of the work. These, when reduced to the essential conditions of rendering, with explanatory details and sections, assume a very different aspect to the original sketch.
The success of the completed work depends upon skilful detailing, which must be thoroughly explicit to be of real value.
For convenience such working drawings are generally made on detail paper, which is usually obtainable in rolls sixty inches wide by twenty-five or fifty yards. This is sufficiently transparent to be employed for tracings, a great convenience when copies are in request, and is a good surface for pen, pencil or chalk, though somewhat thin for colour.
Designs can be sketched in charcoal, and the desired lines drawn in ink. When dry the charcoal lines can be obliterated by rubbing with a leather or soft cloth, by which the charcoal is distributed, forming a tone over the whole surface. This is easily removable by india-rubber, and excellent relief effects can be obtained by judiciously taking out lights and strengthening shadows, though to avoid any possible misunderstanding it is usual to also indicate the relief by sections drawn through the details.