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Technical Drawings give detailed information about Structure, Dimensions, Materials and Assembly

The main ones are Perspectives, Isometric Projections and Planometric Projections

Working Drawings also include Orthographic Projections and Sections

Projections are three-dimensional shapes on a 2D surface

Hands by MC Escher    Image from: Google Search

MC Escher is a very famous graphic artist, known
for his mathematical illusions. His drawings have
inspired many other artists

Image from: Interactive Drawings

Image from: Interactive Drawings

In an Isometric Projection all vertical lines on an object remain vertical while horizontal lines are drawn at 30°

Image from: BBC Bitesize

Isometric projection distorts shapes slightly in order to keep all upright lines vertical (and because perspective is ignored)

Their advantage is that they show the object's dimensions accurately, making it easier to draw them, to scale from the Plan View


Planometric projections (like isometric drawings) show all dimensions accurately and to scale, and are frequently used to show buildings or room layouts

Image from: BBC Bitesize

Because they are drawn with 45° angles, there is no distortion, so that a circular object can be shown as a true circle

In Perspective Drawings the forward face or edge
of the object is drawn first, with the other lines receding away from the viewer, just as they appear when you look
at a real object

Image from: BBC Bitesize

If the receding lines are extended they will meet
together at the Vanishing Points

One Point Perspective    Image from: Andrew Diec

Perspective drawings can use one, two or three
vanishing points

Two Point Perspective    Image from: Andrew Diec

Two-point perspective has many applications
for developing ideas in 3D

Vertical Two Point Perspective    Image from: Andrew Diec

Three-point perspective is sometimes used
for internal views

Three Point Perspective    Image from: Andrew Diec

More often, Three-point perspective is used
for drawings of tall buildings

Image from: Harvest School

The advantage of perspective drawing is that it makes objects appear more realistic, as objects appear to get smaller as their distance from the observer increases

Image from: Google Search

Escher used three-point perspective
in the following drawing

Relativity by MC Escher     Image from: Google Search

This inspired the following model

Image from: Lego

Drawings which contain all the information needed to make an object, including dimensions and details of components, materials and assembly instructions, are called Working Drawings

Although these may be done in Isometric or Planometric projection, the normal drawing technique is orthographic projection

Some objects may need a Section Drawing to give extra structural information, or an Assembly Drawing to show how the parts fit together

Ulster Uni

BBC Bitesize

Technical Drawings give detailed information about Structure, Dimensions, Materials and Assembly

The main ones are Isometric Projections, Planometric Projections and Perspectives

Projections are three-dimensional shapes on a 2D surface, like a sheet of paper. They give the illusion of depth

For working drawings, there are also Orthographic Projections, Sections and Assembly Details

In an Isometric Projection all vertical lines on an object remain vertical while horizontal lines are drawn at 30°

Image from: BBC Bitesize

Isometric projection distorts shapes slightly in order to keep all upright lines vertical (and because perspective is ignored)

Their advantage is that they show the object's dimensions accurately and in the correct proportions, making it easy to draw them from the Plan View and to scale

In Planometric Projections, also called Axonometric projections all vertical lines on an object remain vertical, while horizontal lines are drawn at 45°

Image from: BBC Bitesize

Isometric projection distorts shapes slightly in order to keep all upright lines vertical (and because perspective is ignored)

Their advantage is that they show the object's dimensions accurately and in the correct proportions, making it easy to draw them from the Plan View and to scale

Planometric projections (like isometric drawings) show all dimensions accurately and to scale, and are frequently used to show buildings or room layouts

Because they are drawn with 45° angles, there is no distortion, so that a circular object - say, a stool on the floor - can be shown as a true circle.

Photo taken 20th May '10

Images and text from

BBC Bitesize

Fire Station

The following examples are from my Architecture course


There is something not quite right with this photo...

What type of drawing is shown below?



Why is one of these elevations darker than the other?

BTEC Construction

insert above

There are two basic types of Orthographic Projections:
1st Angle and 3rd Angle

In construction, we generally use 3rd Angle Projection,
to show a building's external elevations and plans

Image from: Topliss (2007) BTEC Construction pg 320

The main view is the South Elevation with the Roof Plan above. The side elevations are positioned on the paper, relative to this main elevation

An Isometric Projection gives a 3D image, with all the lines drawn at the same scale and at an angle of 30°

Image from: Topliss (2007) BTEC Construction pg 320

All the receding lines are parallel, so this is not a perspective, and the plan is skewed into an obtuse angle

An Axonometric is similar to isometric,
but with all the lines drawn at 45°

Image from: Topliss (2007) BTEC Construction pg 321

This method is easier to construct because it uses the true plan, simply rotated by 45°. Also, it appears to give a higher view-point than isometric, that is, it lets you see inside the box

Perspectives give a more 'realistic' view

Image from: Topliss (2007) BTEC Construction pg 321

For a two-point perspective, all lines converge onto two vanishing points, fixed at eye level on the horizon

Perspectives can be drawn to scale but they are quite complicated. The one shown above was generated by
Google Sketch-Up

Exploded Views

Image from: Topliss (2007) BTEC Construction pg 321

Rockport

To completely describe their buildings, architects will use a range of drawing types. These include:

3D Projections
Plans
Elevations
Sections
and Details

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1st Building

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A Perspective is an example of a 3D projection

Image from: McMorrough (2006) Materials, Structures and Standards pg 32

Perspectives are 'Artistic Impressions', they are not used on site to construct the building. But they are very effective in showing how the building would be like if you were actually in the space

Image from: McMorrough (2006) Materials, Structures and Standards pg 32

A Plan is a horizontal section, typically depicting the building as though cut through at 3'-0" from the floor

Image from: McMorrough (2006) Materials, Structures and Standards pg 32

A Section provides a vertical slice of the building. Different line-weights can give information about the materials used

Image from: McMorrough (2006) Materials, Structures and Standards pg 32

An Elevation is the external view. Different line-weights can give the illusion of depth. Shadows provide some sense of 3D

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2nd Building

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Click image to enlarge

Image from: McMorrough (2006) Materials, Structures and Standards pg 43

A Complete Building Plan is usually drawn at a scale to ensure the whole area is seen. Most elements of this plan are keyed to other drawings

Image from: McMorrough (2006) Materials, Structures and Standards pg 44

Elevations describe the external views of the building, usually showing the materials used and important vertical dimensions

Image from: McMorrough (2006) Materials, Structures and Standards pg 44

Reflected Ceiling Plans (RCPs)

Image from: McMorrough (2006) Materials, Structures and Standards pg 46

RCPs may be thought of as upside-down floor plans, because they are literally a plan of the ceiling. They are used to describe light fixtures, ceiling heights and materials

Light fixtures often bear tags that refer to their descriptions in the Lighting Specifications

Image from: McMorrough (2006) Materials, Structures and Standards pg 47

Interior Elevations are drawn to a larger scale to allow for more details, notes and dimensions to be shown

Keyed from the Building Plan, they are also keyed to other drawings, such as sections or cabinet construction

Image from: McMorrough (2006) Materials, Structures and Standards pg 47

Details show specfic areas and are drawn at small scales like 1:5 or 1:10

Image from: McMorrough (2006) Materials, Structures and Standards pg 96

This is another example of a Perspective. The lines converge to a single vanishing point