1 Planning a Drawing Drawings can be drawn as a series of flat views called Orthographic Projection or in a form that resembles the actual appearance called a Pictorial Projection.Drawings can be drawn as a series of flat views called Orthographic Projection or in a form that resembles the actual appearance called a Pictorial Projection. Orthographic projection is the method of showing all the views of an object in separate drawings and in a systematic manner on the same drawing sheet.Orthographic projection is the method of showing all the views of an object in separate drawings and in a systematic manner on the same drawing sheet. This method is used for construction drawings and shows the plan view, elevations and sections of a building or components of a building.This method is used for construction drawings and shows the plan view, elevations and sections of a building or components of a building. Most constructional drawings are of this nature.

2 Orthographic Projection There are two main methods of orthographic projection:There are two main methods of orthographic projection:  First Angle Projection  Third Angle Projection ( Used for engineering drawings) An orthographic drawing can be recognised as either first angle or third angle projection by a symbol, which will be included on the drawing.An orthographic drawing can be recognised as either first angle or third angle projection by a symbol, which will be included on the drawing. The recognised symbol for First Angle Projection is as follows:The recognised symbol for First Angle Projection is as follows: The recognised symbol for Third Angle Projection is as followsThe recognised symbol for Third Angle Projection is as follows

3 First Angle projections First Angle projections are used for building drawings The projected faces which represent the sides of the object are known as elevations and those viewed looking down or up from below are known as plans.The projected faces which represent the sides of the object are known as elevations and those viewed looking down or up from below are known as plans. The views should be set out on the drawing paper in a special format.The views should be set out on the drawing paper in a special format.  The front elevation is drawn first and all the other views are related to it.  The plan of the building is always drawn directly underneath the front elevation.  The view from the left is placed to the right of the front elevation and the view from the right is placed on the left of the front elevation.  A view from the rear may be placed to the left or right depending on space and personal choice.  A section is placed at the opposite side to the intended view.

4 First Angle projections

5 Pictorial Projection This is a method of drawing objects in a three dimensional form and the object is easily recognised from the finished drawing.This is a method of drawing objects in a three dimensional form and the object is easily recognised from the finished drawing. There are number of different pictorial projection methods of depicting objects or buildings.There are number of different pictorial projection methods of depicting objects or buildings.  Isometric Projection  Axonometric Projection  Oblique Projections

6 Isometric Projection In this form of pictorial projection all the vertical lines remain vertical but all the horizontal lines are drawn at angle of 30º to the horizontal.

7 Axonometric Projection In this form of pictorial projection all the vertical lines remain vertical but all the horizontal lines are drawn at angle of 45º to the horizontal

8 Oblique Projections This is another form of pictorial projection which can be either:This is another form of pictorial projection which can be either:  Cavalier  Cabinet CavalierCavalier  All vertical lines are drawn vertical and all horizontal lines in the front elevation are drawn horizontal to give a true front view or elevation. All horizontal lines in the side view or elevation are drawn full length at 45º to the horizontal. CabinetCabinet  All vertical lines are drawn vertical and all horizontal lines in the front elevation are drawn horizontal to give a true front view or elevation. All horizontal lines in the side view or elevation are drawn to half their full length at 45º to the horizontal.