To get an idea about the subject used his image on paper or screen.Typically, the image of the subject with any one of the parties does not give a full picture of its form, it is required to obtain its projection on two or three planes.To streamline the process of projection, the plane on which the projection takes place, perpendicularly to each other.Consider, what are the different types of planes.A total of three, and they form a triangular space in a right angle.
Each of the projection planes has its own name and letter designation.Frontal plane - a vertically placed before our eyes the plane of projection.For clarity - a plane to which we are facing, r. E. The plane of the considered picture.Represented frontal plane Latin letter V.
horizontal plane is perpendicular to the front.Figuratively speaking, the horizontal plane - this is a plane that lies with us "under his feet."It is usually denoted by the letter H.
third of the main projection planes is called a profile.As the frontal plane, which is vertical and forms a right angle with the previous two.Indicate profile plane Latin letter W.
When pairwise intersection of these three planes formed coordinate axis x, y, z.This mutually perpendicular rays with a common vertex at the intersection of the three planes of projection, denoted by the letter O.
To get a detailed image of the object, it is required to combine the images obtained in three mutually perpendicular faces.To this end, the two faces of the angle expand and combine with the third.Frontal plane remains stationary horizontal rotated downward by 90 ° along the x-axis, a profile plane is rotated by 90 ° to the right along the axis z.Thus the last two plane aligned with the front (located below the horizontal, the profile - to the right).
in descriptive geometry, any arbitrary location of the plane in the drawing can be defined in different ways: three projections do not lie on a straight points and projection of the line a point outside it, as well as projections of parallel or intersecting lines or a plane figure.
relatively basic projection planes can take the plane of the following provisions:
1. It may be non-perpendicular to any of them.Then it - t. N.plane of general position.
2. It may be perpendicular to one of the three projection planes.In this case, it is called horizontal projecting, projecting profile-or front-projecting, respectively, of the plane, which is perpendicular to it.
3. The plane may be perpendicular to two of them and parallel to the third.She is called the front, horizontal or profile respectively.
Direct may take the following provisions with respect to the plane:
1. belong to her.
2. be parallel to it.
3. intersects the plane (a special case - in the form of perpendicular)
In the plane there are main lines, called contour and Frontale.It lines lying in the plane and parallel to the respective planes of projections.
any plane can be represented in the form m. N.trace of the plane, that is, the lines along which it intersects the plane of projection.The tracks are also called horizontal plane, the frontal and profile.At the intersections with the plane of the axes of the projections on the axes there are points of mutual intersection of the plane of the traces, which is usually called the vanishing point for the next plane.
horizontal and frontal plane of the traces on the projection plane coincide with their projections of the same name.It should also be mentioned that any horizontal one and the same plane parallel to each other and parallel to the horizontal track, as well as any of its frontal mutually parallel and parallel to its front end trail.
