1.58k likes | 2.05k Views
Descriptive Geometry Eng. Areej Afeefy. Ref. Descriptive Geometry Metric PARE/LOVING/HILL Fifth edition. Descriptive Geometry. Descriptive Geometry: is the science of graphic representation and solution and space problems. By Arch. Areej Afeefy. projections.
E N D
Descriptive GeometryEng. AreejAfeefy Ref. Descriptive Geometry Metric PARE/LOVING/HILL Fifth edition
Descriptive Geometry • Descriptive Geometry: is the science of graphic representation and solution and space problems By Arch. Areej Afeefy
projections • Two common types of projections: 1) perspective projections (used by architects or artists) 2) orthographic projections (perpendicular to the object)
Perspective Projection Screen Human eye
Orthographic Projection Screen
Orthographic Projection Horizontal Front Profil
Horizontal Profil Front
Steps to obtain a view • Establish the line of sight. • Introduce the folding line • Transfer distances to the new view • Determine visibility and complete the view
Step 1: Establish the line of sight. Primary Auxiliary Views Step 2: Introduce the folding line Step 3: transfer distances a,e d,h y b,f c,g H 1 Step 4: determine visibility and complete view D2 1 D1 D y h d g k1 e D2 c y f a D1 f,e g,h b b,a c,d
All views projected from top view has the same height dimension
All the views projected from front view have the same depth dimension
the true angel between a line and any projection plane appears in any view shows the line in true length and the projection plane in Edge View.
Bearing , Slope, and Grade N N aH aH S55oE 55 b b Bearing: a term used to describe the direction of a line on the earth’s surface
Azimuth Bearing N aH aH 125o N125o b b
problem • A 160-m segment AB of a power line has a bearing of N 60o and a downward slope of 20o from the given point A. Complete the front and top views. ah aF
D1 D1 D1 D1 b 1 20o H 160 m N b N 60o a1 ah H F aF b
Grade Grade: another way to describe the inclination of a line from the horizontal Plane
Chapter 4 Planes