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6 Dashes
\curvedashes must first define a dash pattern with length greater than 0pt. Many symbol and pattern combinations are possible. The fixed number and fixed spacing methods of symbol drawing described in Section 5 work with three methods of drawing dashes which are:
1. if there is no symbol count and no symbol, a dash pattern with its length reduced by \csdiameter is drawn between symbols spaces of width close to \csdiameter to give an overall spacing equal to the pattern length specified by the \curvedashes command;
2. if there is a symbol count but no symbol, the dash patterns drawn have their length equal to that defined by \curvedashes with \csdiameter gaps at symbol positions;
3. if there is a symbol count and a symbol, the dash patterns drawn have their length adjusted slightly so an integral number of patterns fit between symbol positions.
Dash pattern commands for centrelines follow for the three techniques above in order:
__
\linethickness{0.25mm}
_\curvedashes[1.2mm]{0,8,1,3,1,8}
_\settowidth{\csdiameter}{00}
_\put(0,20){\curve(0,0, 30,5, 60,0)}
_\put(0,10){\curve[1](0,0, 30,5, 60,0)}
_\curvesymbol{\thepin\addtocounter{pin}{1}}
_\setlength{\csdiameter}{2\csdiameter}
_\put(0,0){\curve[1](0,0, 30,5, 60,0)}
_
The following figure shows the resulting dash patterns. The upper line has first position blank because the \overhang is 0pt. It has patterns shrunk to scale between symbol spaces e.g., 1 to 2, and symbol space centres one pattern length apart. The middle line has patterns close to defined length but with the first dash part blanked by half of symbol space 3 and the second pattern broken in its first dash by symbol space 4. The lower line patterns are stretched between symbol spaces. Which pattern is appropriate depends on picture meaning and function.

Centrelines and Symbols


R.N. Roth and I.A. van Haeringen, The Australian Engineering Drawing Handbook, Part 1 Basic Principles and Techniques, The Institution of Engineers, Australia, Canberra, 1986.