7.4.3. True Size (Shape) Of An Oblique Plane
When the line of sight is perpendicular to the edge view of a
plane, it projects as true size (shape). The true size view is
projected parallel to the edge view of the plane. Therefore the
fold line between the views is drawn parallel to the edge view.
An oblique plane does not appear as true size in any of the
principal projection planes. Therefore a primary and
secondary auxiliary view is needed to solve for the true shape
of an oblique plane.
In figure 8.6, oblique plane 1-2-3 is given and its true shape is
required.
Step 1: Draw a horizontal line 1F-4F parallel to the H/F and
show it as true length in the horizontal view.
Step 2: Draw H/A perpendicular to line 1H-4H and complete
auxiliary view B. Line 1A-4A is a point view and plane
(^1) A-2A-3A an edge.
Step 3: Project secondary auxiliary view B parallel to the edge
view of plane 1A-2A-3A. Draw A/B parallel to the edge
view.
Step 4: Complete auxiliary B; plane 1B-2B-3B is true size
(shape)
Note that: In a true size/shape view of a plane, all lines are
true length and all angles are true angle.