Elements of descriptive geometry, with applications to isometric projection and othe forms of one-plane projection; a text-book for colleges and ingineering schools by O. E. Randall.

ISOMETRIC PROJECTION

205

coincide with the isometric axes o'-x' and o'-y' respectively. Third,
when the isometric projections of the axes C-D and C-B coincide
with the isometric axes o'-z' and o'-y' respectively.
In each case the isometric projections of the points are found
by use of the coordinate measurements made in Fig. 183. For
example, the point p', Fig. 182, is obtained by making o'-w' and
w'-p' equal respectively to A-W and W-P of Fig. 183.
Xt
sfc>' O. F B
Iyr
FIG. 184 FIG. 185
The point 1"' is located by making o'-u' and u'-l"' equal respectively to C-U and U-L of Fig. 183.
446. Problem 310. To make an isometric drawing of any plane
curve.
See Figs. 184 and 185. Let Fig. 185 represent the curve when
referred to two rectangular axes, one of which is 0-A tangent to
the curve at D and the other O-B tangent to the curve at F.
The coordinates of a number of points, W, R, D, F, M, Q, on
the curve are determined with reference to these axes.
The isometric projection of this curve is shown in Fig. 184,
where the isometric projections of the axes 0-A and 0-B coincide
with the isometric axes o'-y' and o'-x' respectively, and where the
isometric projections of the points W, R, D, etc., are found as
previously explained.
We may draw the isometric projection of this curve when the
curve occupies any desired position with reference to the coordinate
axes 0-X, 0- Y, and 0-Z, whether in the plane determined by any two
of these axes or in the space-angle determined by the three axes.