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The horizontal and frontal traces meet in the point in which the given plane cuts the axis x.
The horizontal and profile traces meet in the point in which the given plane cuts the axis y. The
frontal and profile traces meet in the point in which the given plane cuts the axis z (Fig. 4.3).
The visualization of a plane from its traces is an entirely different process from reading the
projection of a line or a point. The traces of the plane oblique to horizontal Π 1, frontal Π 2 and
profile Π 3 planes of projection are not projections of the plane in the ordinary sense.
Plane is not limited to the portion of the plane in the first angle. Producing the traces through
x, we have immediately, the traces of the portions of the plane in all of the other angles. The traces
of a plane are not limited by x.

4.3 POSITION CLASSIFICATION

Particular position of the plane
Planes are general positions and particular.
The general provisions plane (oblique) is not parallel and is not perpendicular any of planes
of projections.
The plane of particular position is parallel or perpendicular at least to one of planes of
projections. Planes of particular position share on two groups:
Projecting planes (inclined) - perpendicular to one plane of projection and inclined to two
another.
Level planes are perpendicular to two planes of projection and parallel to another of them.
Projecting planes can be in three positions:
Plane is perpendicular a horizontal plane of projection and an inclination to face-to-face and
profile planes (Fig. 4.4). It is called horizontal-projecting plane;

Figure 4.4

The frontal and profile traces of this plane are parallel to the axis z.
Plane is perpendicular a face-to-face plane of projection and an inclination to horizontal and
profile planes (Fig. 4.5). It is called frontal-projecting plane;

Figure 4.6

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