Su33 Plane Orthographic Drawing

A three-dimensional object can be repre­sented in a single aeroplane, such equally on a sail of paper, using projecting lines and planes. All projection theory is based on two variables: line of sight (projecting lines) and plane of projection.

A line of sight (LOS) is an imaginary line between an observer's eye and an object. A plane of projection (i.due east., an paradigm or motion-picture show plane) is an imaginary flat airplane upon which the image is projected. The project is produced by connecting the points where the lines of sight pierce the projection plane. Equally a outcome, the 3D object is transformed into a 2D view.

If the distance from the observer to the object is infinite, so the projection lines are assumed to be parallel, and the project is called a parallel projection. Parallel projection is orthographic if the plane of project is placed betwixt the observer and the object, and the plane is perpendicular to the parallel lines of sight.

Yous can use parallel projection technique to create both multiview and pictorial (isometric and oblique) views.

1. In multiview orthographic projection (run across details below), the object surface and the projection plane are parallel, and you lot can see merely two dimensions.
2. In isometric view (orthographic) the surface is no longer parallel to the project aeroplane, simply the latter is perpendicular to the lines of sight, with three dimensions existence seen.
3. In oblique projection (non-orthographic) the object surface and the projection plane are also parallel, simply the lines of sights are non perpendicular to the projection plane, and you can encounter over again three dimensions.

If the distance from the observer to the object is finite, so the projection lines are not parallel (since all lines of sight start at a single indicate), and the drawing is classified equally a perspective projection. In perspective view the object surface and projection plane tin can exist also parallel.

Multiview projection

By irresolute position of the object relative to the line of sight y'all can create different views of the same object. Cartoon more than than one face of an object by rotating the object relative to your line of sight helps in understanding the 3D form. Having several views on 1 drawing y'all utilize the concept of multi-view projection, which is based on the orthographic (parallel) projection technique where

• the airplane of projection is positioned between the observer and the object,

• the plane of projection is perpendicular to the parallel lines of sight, and

• the object is oriented such that only ii of its dimensions are shown.

Main principles of creating multiview projections

The plane of projection can be oriented to produce an infinite number of views of an object. However, the most common views are the six mutually perpendicular views that are produced by vi mutually perpendicular planes of projection:

• Front view – the one that shows most features or characteristics.
• Left side view – shows what becomes the left side of the object after establishing the front view position.
• Right side view – shows what becomes the right side of the object after establishing the front end view position.
• Top view – shows what becomes the top of the object once the position of the front view is established.
• Bottom view – shows what becomes the bottom of the object one time the position of the front view is established.
• Rear view – shows what becomes the rear of the object once the position of the front view is established.

The most informative (descriptive) view of the object to be represented is normally chosen every bit the principal view (front view). This is view A related to the respective direction of viewing A and it unremarkably shows the object in the functioning, manufacturing, or mounting position.

View positions on drawings and corresponding viewing directions

Positions of the other views relative to the principal view in the drawing depend on the projection method.

The number of views and sections must exist limited to the minimum necessary to fully represent the object without ambivalence.

Unnecessary repetition of details must be avoided.

Conventional view placement

More often than not, three views of an object are enough, nevertheless, a cartoon must contain equally many views as necessary to illustrate the part, usually at right angles to one another.

Frontal plane of project

In multiview projection, the object is viewed perpendicular to the main faces, and then that but one face of the object is depicted in each view. The frontal plane of project is the plane onto which the front view of a multiview drawing is projected.

In the front view you can encounter superlative and width of the object, simply you cannot run into its depth.

Horizontal plane of projection

The top view is projected onto the horizontal plane of projection, which is airplane suspended in a higher place and parallel to the meridian of the object.

The pinnacle view of an object shows the width and depth dimensions.

Profile aeroplane of projection

In multiview drawings, the correct side view is the standard side view. The right side view is projected onto the right profile plane of project, which is a plane that is parallel to the right side of the object. However, you lot can also use the left side view if it is more descriptive and informative. Moreover, when needed, you tin include both side views into one cartoon.

The side view of an object shows the depth and height dimensions.

The three-view multiview drawing is the standard used in engineering and technology, considering oft the other three mutual views are mirror images and do not add together to the knowledge almost the object.

The standard views used in a three-view drawing are the

• top,
• front end, and
• correct side views,

arranged as shown in the effigy:

The width dimension is common to the front and top views. The height dimension is common to the front and side views. The depth dimension is common to the acme and side views.

For simple parts one or ii view drawings will often exist enough. In ane-view drawings the 3rd dimension may exist expressed by a note, or by descriptive words, symbols, or abbreviations, such equally Ø, HEX, etc.

Foursquare sections may be indicated by lite crossed diagonal lines, every bit shown in a higher place, which applies whether the face is parallel or inclined to the drawing plane.

Some other example of a ane-view drawing:

Additional views may be added if they improve visualization.

The views should too be called to avoid hidden feature lines whenever possible. That means that the virtually descriptive view should be shown.

Besides, yous should select the minimum number of views needed to completely describe an object. Eliminate views that are mirror images of other views.

Why multiview drawings technique is and then important?

To produce a new product, it is necessary to know its true dimensions, and true dimensions are not adequately represented in most pictorial drawings. For example, the photograph is a pictorial perspective paradigm. However, as you lot can meet, the epitome distorts truthful distances, while the latter are essential for manufacturing and construction, and in this instance the case in question is the width of the road, not the electrical pole!

In mechanical applied science perspective projections distort measurements.

As you tin see, the two width dimensions in the front view of the cake appear different in length in the perspective projection. In other words, equal distances exercise not appear equal on a perspective cartoon.

Thus, since applied science and applied science depend on exact size and shape descriptions for design, the best arroyo is to employ the parallel projection technique (orthographic project) to create multi-view drawings where each view shows but two of the three dimensions (width, height, depth).

To summarize:

The advantage of multiview drawings over pictorial drawings is that multiview drawings shows the true size and shape of the various features of the object, whereas pictorials distort true dimensions which are critical in manufacturing and construction.

ane^st & 3^rd angles (glass box)

What exactly you should place on the right side project?

Is it that nosotros tin see from the left side, or from the right side of the object?

To answer these questions there are two different ways, based on two different principles

• Beginning-Angle Projection
• Third-Angle Projection.

Third bending is used in Canada and the United States. First angle is used in Europe.

In third angle orthographic projection the object may be causeless to be enclosed in a glass box.

Each view represents that which is seen when looking perpendicularly at each face of the box.

The resulted views are identified by the names as shown.

The front end, rear, and side views are sometimes called eleva tions, e.k., front end acme. The top view may be termed the program.

If desired, the rear view may be shown both ways – at the extreme left or the extreme right. When this is not practical to show rear view at he farthermost left or right due to the length of the part, especially with panels and mounting plates, the rear view should not be projected upwards or down, as this would consequence in its being shown upside downwards.

Instead, information technology should be drawn as if projected sideways, but located in some other position, and should be clearly labelled REAR VIEW REMOVED.

In commencement angle orthographic projections the object is considered equally being rolled over to either side, so that the right side of the object is fatigued to the left of the front elevation:

Information technology is mandatory to indicate the method of multiview projection by including the appropriate ISO (International Organization for Standardization) projection symbol – the truncated cone:

You should identify this symbol in the lower right-mitt corner of the drawing in or adjacent to the championship cake.

Axonometric project

It is i of the pictorial drawing pro­jections, which are useful for illustrative purposes, educational aids, installation and maintenance drawings, blueprint sketches, and the like.

The Greek give-and-take axon means axis and metric means to measure out. Axonometric projection is a parallel projection technique used to create a pictorial drawing of an object by rotating the object on an axis relative to a airplane of projection.

Axonometric projections such equally isometric, dimetric, and trimetric projections are ortho­graphic, in that the project lines are all parallel, simply the bending of views is then chosen that three faces of a rectangular object would be shown in a unmarried view.

Axonometric drawings are classified by the angles between the lines comprising the axonometric axes. The axonometric axes are axes that meet to form the corner of the object that is nearest to the observer.

When all iii angles are unequal the cartoon is classified as a trimetric. When two of the three angles are equal the cartoon is classified as a dimetric. When all 3 angles are equal the cartoon is classified as a isometric.

Although there are an space number of positions that can be used to create such a drawing but few of them are used.

Enlarged detail

To eliminate the crowding of details or dimensions, an enlarged removed view may exist used.

• The enlarged view should be oriented in the same fashion as the principal view,
• the calibration of enlargement must be shown, and
• both views should exist identified past one of the methods shown in the illustrations – with the leader line or with the circle line. The circle enclosing the area on the main view should be drawn with a thin line.

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Source: https://www.mcgill.ca/engineeringdesign/engineering-design-process/basics-graphics-communication/projections-and-views

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