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DrawingTypes

&Construction

Drawings

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Building projects require several types of specialised drawings.This collection of drawings, known as a project set, includes:

� Location Plan� Site Plan� Floor Plan� Elevation� Sectional Views� Rendered Illustrations

Buildings are designed by architects along with various othermembers if a design team. The team ensures the building meetsthe needs of the client and satisfies local authority planningdepartment and building control regulations.

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A Location plan shows where the site is located within the local area.

It shows:

� Roads� Outlines of buildings� Site boundaries� North Sign� Land contour lines

Location Plan

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A site plan shows the building within their site/boundary. The buildings areShown as outlines and the boundaries marked slightly darker.

It shows:

� Plot Number� Waste pipe runs� Manholes� Trees� Contour lines� Position of building

Site Plan

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Floor PlanA floor plan shows the layout of the room inside the building and the positionOf the doors, windows and other important objects.

Architects often use several layers to show different types of fixtures andFittings Such as plumbing, electric wiring etc.

Scale 1:50

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ElevationUsed to show the outside features of a building, including position of the door,Windows etc.

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Sectional Drawing

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First Angle Projection

First angle projection is a method of creating a 2D drawing of a 3D object.

Note the symbol for first angle orthographic projection.

This is important information for the person interpreting the drawing becauseif you examine the diagram below you will note that in first angleorthographic projection:

• the view from the front is in the middle

• the view from the left is on the right

• the view from the right is on the left

• the view from the top is on the bottom

• the view from the bottom is on the top

• the view from the rear is on the far right.

Third Angle Projection

Third angle projection is a method of creating a 2D drawing of a 3D object.

Note the symbol for third angle projection.

This is important information for the person interpreting the drawing becausein third angle projection:

• the view from the front is in the middle

• the view from the left is on the left

• the view from the right is on the right

• the view from the top is on the top

• the view from the bottom is on the bottom

• the view from the rear is on the far right

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Orthographic Drawings

In engineering, a technique called orthographic projection is used to showa three dimensional object as a two dimensional drawing.

Orthographic projection allows all possible views of a three dimensionalobject to be shown in a two dimensional drawing.

It uses multiple views of the object, taken from points of view rotated about theobject's centre through increments of 90°.

Isometric DrawingsIsometric drawings are 3D drawings.

They show three sides, all in dimensional proportion, but none are shown as

a true shape with 90 degree corners.

All the vertical lines are drawn vertically

All horizontal lines are drawn at 30 degrees to the base line.

Isometric is an easy and realistic method of drawing 3D images.

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Oblique Drawings

Oblique drawings are also used in engineering.

The object is drawn with the most distinguishing features facing directlytowards the observer, showing the true shape of these features.

To show the 3D effect, parallel lines (called ' lines of sight') are drawn fromthe front face at an angle of 45 degrees.Distances are halved on the 45 degree line.

Circular features like round holes can be drawn on this front face as true circles.

Planometric DrawingsThe difference is that instead of the front view being a true view as in

OBLIQUE; the PLAN view is the true view in PLANOMETRIC.

However the plan view is drawn at 45° or 30°/60°.

The angle between the lines is always 90°.

The front and side views are projected upwards from the plan.

Planometric is very popular with architects whena plan is often the most important view.

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Perspective Drawings

Perspective drawings show objects as you would see them in the real world -in three dimensional view.

The lines of sight in a perspective drawing can be projected to a vanishingpoint in the distance. This is what gives the appearance of depth.

Perspective drawings are a 3D representation of an object but theproportions are not true – they are distorted to give the perception of depth.Also the detail at the farthest ends can be difficult to see because it is so small.

Sectional Drawings

Section or cross section drawings show a product as if it has been sliced in half.

The imaginary cut is called a section plane which is sometimes representedby a line consisting of long and short dashes.

Parts of the object that are cut through are shaded by cross-hatching.

If two parts touch, then the cross-hatching goes in opposite direction. Partssuch as nuts and bolts, studs, screws, shafts, gear teeth, roller bearings, ballbearings, webs and axles are not sectioned.

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Assembly Drawings

An assembly drawing shows how parts of a product fit together.

They are often used to show how to assemble parts of model kits andflat-pack furniture.

There are two types:

A fitted assembly drawing shows the parts put together.

An exploded drawing shows the parts separated,but in the correct relationship for fitting together.

Hidden Detail on DrawingsMany objects have internal features, such as holes, slots and grooves.These features cannot be seen when viewed side on in real life, but can be

represented as hidden outlines (ie dashed lines) in drawings.

Parts of an object may also conceal other parts and so the hidden partsmay be shown on a drawing as hidden outlines.