Plans and Elevations_lecture.pptx

Plans and Elevations Objectives of Learning Draw orthogonal projections. Draw the plan and elevations of an object to scale. 1 Orthogonal Projections 2  What is a plane and a normal to a...

Plans and Elevations Objectives of Learning Draw orthogonal projections. Draw the plan and elevations of an object to scale. 1 Orthogonal Projections 2  What is a plane and a normal to a plane? A plane is the flat surface of an object. There are three types of planes, namely horizontal plane, vertical plane and inclined plane. A normal to a plane is a straight line that is perpendicular or that forms a right angle to any line on the plane. 3  Orthogonal Projections The diagram below shows a quarter of a right cylinder with a horizontal base PQRS. Both PSTU and PQRS are planes and QRTU is a curved surface. 4  Orthogonal Projections The diagram below shows a right prism with a horizontal plane ABCD. ABF and CDE are vertical planes. BCEF and ADEF are inclined planes. The lines FM and EN are perpendicular to the lines AB and CD respectively. The lines FM and EN are also known as the normal to the plane ABCD. 5 The diagram on the right shows a cube. State the normal to the following planes. (a) PQRS (b) PSTU (c) RSTW (d) QRTU 6 7 The diagram below shows a right prism with a rectangular base ABCD. M and N are the midpoints of AB and CD respectively. Given FG = EH = DN = NC = AM = MB, state the normal to the following planes: (a) ABCD (b) ADEF 8 9 10 11 12 13 14 15 16 17 Orthogonal Projections 18 19 20 21 22 23 24 25 26 26  “clear logical patient style which takes the student seriously” - John Spencer Engineering Math 061 27