2. INTRODUCTION
A plane is a two dimensional object having length
and breadth only. Its thickness is always neglected;
various shapes of plane figures are considered
such as square, rectangle, circle, pentagon,
hexagon, etc.
5. A Plane is a two dimensional entity having only length
and breadth with negligible thickness which is
considered as zero.
TYPES OF PLANES
Planes may be divided as two main types. They are
(I) Perpendicular Planes
(II) Oblique Planes.
Perpendicular Planes
Planes which are perpendicular to any one of the
principal planes of projection are called as
perpendicular planes. These planes may be inclined or
parallel to the other principal plane.
6. Various positions of
perpendicular planes
(a) Planes perpendicular to V.P. And Parallel to H.P.
Consider a plane perpendicular to V.P. And Parallel to H.P. The top
view reveals the true shape of the plane
the front view is a line parallel to xy line.
7. (b)Planes perpendicular to H.P. And Parallel to V.P.
Consider a plane perpendicular to H.P. And Parallel to V.P.
The front view shows the exact shape and size of the plane.
The top view is a line parallel to xy line
8. (c) Plane perpendicular to both H.P. And V.P.
Consider a plane in space which is perpendicular to
both the H.P & V.P.
Both the front view and top view of the plane appear
as a straight lines on a single projector.
9. (d) Plane perpendicular to V.P. And inclined to H.P.
Consider a plane perpendicular to V.P. And inclined at an
angle to the H.P. The top view is shorter than its ture size.
The front view is a line inclined at an angle to xy line .
10. (e) Plane perpendicular to H.P. And inclined to V.P.
Consider a plane perpendicular to the H.P. And inclined at
an angle to the V.P. The front view is shorter than its true
size.
The top view is a line inclined at an angle to xy line.
11. (f) Surface of the plane kept inclined to HP and
VP or OBLIQUE PLANE
Consider the plane to be inclined to both the surfaces
that is the Horizontal plane and the Vertical plane
12. Example
A plate having a shape of an isosceles
triangle has base 50mm and altitude
70mm. It is so placed that in the front
view it seen as an equilateral triangle of
50mm side and one side is inclined at 45
deg to xy .
13. SOLUTION
Front view is seen as an equilateral triangle of 50mm side and one side is
inclined at 45 deg to xy
isosceles triangle has base 50mm and altitude 70mm.
Projections of Planes Peculiar problem wherein plane surface is inclined to
both the planes
Draw the side view and rotate the side view to get the true inclinations with
VP and HP as well as the top view.
Don’t forget to denote the points with appropriate notations