Page 150 - Engineering drawing from first principles using AutoCAD

Three-dimensional projection exercises 143

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Figure 6.22

Start at the left side and draw a pair of vertical lines between the curve limits, and where
they intersect the outside profile project circles across to intersect the flute profiles.
Transfer the intersection points on the flutes back to the vertical lines but use the
ZOOM command at its highest magnification for accuracy. It is also advantageous with
a small screen to use the EXTEND option. The view with the flutes could take up most of
the screen, but if lines from the intersections are accurately positioned and projected to
the left side of the screen they can easily be extended. Use ZOOM again to draw a polyline
through the left-hand plotted points. Now use the FIToption from the EDIT POLYLINE
menu to convert the polyline into a curve. In Fig. 6.23 I have only left the construction