Here's another way of building a parallel line:
Needed analogue tools:
Dividers
Pencil
Straight Edge
Eraser
Given:
Line A-B
m-n: Desired offset distance
Desired:
Line C-D (with an m-n offset distance)
Measure line m-n with your dividers. Place one leg on B, the other on line A-B. Mark that new intersection as a.
Draw an arch with center a and radius m-n.
Mark b at the new intersection of the arch and line A-B.
With the divider's stretch of m-n, set one leg on point b and the other on the arch (Step 2).
Mark the new interesection of the dividers and the arch as c.
Connnect with a straightedge points b and c.
Continue that same b-c line upwards till b-c euqals c-d.
Connect d and a.
Mark point e at the intersection of d-a and the arch (Step 2).
Continue line d-a further down. Measure distance e-a with the dividers. Set one leg on a and the other on the extended line d-a. Mark that new intersection as f.
Using the straightedge, draw a line starting from f with any angle/direction. Make sure it crosses line A-B.
Mark the new intersection as h.
Measure distance f-h with your dividers. Set one leg on h and the other on the line. Mark a new point g where the second leg crosses the line (Step 11).
Place the straighedge on points g and e and draw a line. Mark points C and D anywhere along the path.
This new line C-D parralels line A-B at a distance m-n.
You can download the CAD and GH (Rhino/Grasshopper) files here:
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