Elements of Descriptive Geometry

3RD ANGLE A-B and C-D Analysis b₁ base circle cone Construction cube cutting plane cylinder Descriptive Geometry determine the true develop the surface dihedral angles draw the third edge equal G₁-L₁ given angle given line given point given straight line H see Fig hence horizontal piercing point horizontal projection horizontal trace HR hyperboloid inclined to H isometric projection line A-B line in space line of intersection parallel to G-L parallel to H pass a plane pendicular perpendicular to G-L perpendicular to H Perspective pierce H plan and elevation plane of projection plane perpendicular point in space prism PROBLEM pyramid radius represent required angle required plane revolution Revolve the line revolved position ruled projector shown in Fig Small 8vo space projector sphere surface of revolution swing tangent third angle plan tion triangle true form true length vertical piercing point vertical plane vertical projection vertical trace VR wire