Thick and Thin of It
The draftsman has a way of making the lines speak for themselves. In the draftsman's language, symbols and conventions are his words. His vocabulary has lines of all types. There are thick lines, thin lines, dotted lines, dashed lines, straight lines, and curved lines. Each has a different meaning and function. The draftsman's language, like any language, depends on a mutual knowledge of the symbols. The theatre, more than any other craft, relies on this mutual understanding to coordinate all phases of a stage production.
The first and simplest convention is the drawing of lines in different weights or thicknesses. The various types of line symbols are grouped into three weight classes: light, medium, and heavy. A line is made heavy or light depending on its eye-catching importance on the blueprint. Obviously, heavy lines are going to be seen first, medium-weight lines second, and lightweight lines last. Beyond the descriptive quality of the weight of a line there is the meaning or symbol of the function implied in the use of certain lines that needs to be explained.
It is easiest to begin with the medium- weight lines, for they are used the most and have already been seen in the working drawing of the three-step. They are the outline lines that represent the shape of the object, showing the edges and surfaces as they appear at the angle of the view. The visible outline is a solid line indicating the visible surfaces. The hidden, or invisible, outline is a dotted line indicating the hidden surfaces, not visible in the view.
Frequently the draftsman will want to show where an adjoining element of scenery touches the surface of an object or the alternate position of the same object. The phantom line symbolizes the removed object by outlining its position in the view. The designer has a choice of the symbols: a dashed line or the repetition of an elongated dash and two dots. Because a phantom line should always carry a label, the choice of line depends on the complexity of the outline of the removed part. Whichever symbol is chosen should be used consistently throughout the drawing.
The lightweight lines are many and varied in uses. Their function is to give additional information about the object and still not detract from the overall picture created by the outlines. That's why they are light in weight.
Dimension lines, with arrowheads at the ends, mark the extent of the surface that is being dimensioned. Figures, set into the line, show the exact distance. If