Oblique projection is defined as a pictorial projection in which projectors are parallel to each other and inclined to the plane of projection at any angle other than right angle. Orthographic and oblique projections. In orthographic projections (both multiview and axonometric) the projectors are parallel to each other and perpendicular to the plane of projection. | Oblique Projections Oblique Sketches Show exact size and shape of one face of an object Object face with most detail parallel to view plane Relatively easy to draw Oblique Axes Oblique Sketch Oblique Projection Geometry One face of object parallel to projection plane Parallel projectors make an oblique angle with projection plane object image Oblique Projection Angle (a) Angle of intersection of projector with projection plane Determines type of oblique projection (Cavalier, Cabinet, General) Classes of Oblique Projections Type of Oblique Oblique Projection Angle (a) Receding Axis Scale Cavalier 45° 1 Cabinet ° 1/2 General 45° < angle < ° ½ < scale < 1 Cabinet vs Cavalier Cavalier a = 45° RA scale = 1 Cabinet a = ° RA scale = 1/2 Receding axis Receding Axis Angle Normally chosen to be 30 °, 45 °, or 60 ° Determines relative emphasis of receding planes Related to angle of rotation of projector about the projection plane normal (b) Receding Axis Angle - 2 projector normal Oblique Projection Generation Oblique Projections C’est . | Oblique Projections Oblique Sketches Show exact size and shape of one face of an object Object face with most detail parallel to view plane Relatively easy to draw Oblique Axes Oblique Sketch Oblique Projection Geometry One face of object parallel to projection plane Parallel projectors make an oblique angle with projection plane object image Oblique Projection Angle (a) Angle of intersection of projector with projection plane Determines type of oblique projection (Cavalier, Cabinet, General) Classes of Oblique Projections Type of Oblique Oblique Projection Angle (a) Receding Axis Scale Cavalier 45° 1 Cabinet ° 1/2 General 45° < angle < ° ½ < scale < 1 Cabinet vs Cavalier Cavalier a = 45° RA scale = 1 Cabinet a = ° RA scale = 1/2 Receding axis Receding Axis Angle Normally chosen to be 30 °, 45 °, or 60 ° Determines relative emphasis of receding planes Related to angle of rotation of projector about the projection plane normal (b) Receding Axis Angle - 2 projector normal Oblique Projection Generation Oblique Projections C’est tout! | Oblique Projections Oblique Sketches Show exact size and shape of one face of an object Object face with most detail parallel to view plane Relatively easy to draw Oblique Axes Oblique Sketch Oblique Projection Geometry One face of object parallel to projection plane Parallel projectors make an oblique angle with projection plane object image Oblique Projection Angle (a) Angle of intersection of projector with projection plane Determines type of oblique projection (Cavalier, Cabinet, General) Classes of Oblique Projections Type of Oblique Oblique Projection Angle (a) Receding Axis Scale Cavalier 45° 1 Cabinet ° 1/2 General 45° < angle < ° ½ < scale < 1 Cabinet vs Cavalier Cavalier a = 45° RA scale = 1 Cabinet a = ° RA scale = 1/2 Receding axis Receding Axis Angle Normally chosen to be 30 °, 45 °, or 60 ° Determines relative emphasis of receding planes Related to angle of rotation of projector about the projection plane normal (b) Receding Axis Angle - 2 projector normal Oblique Projection Generation Oblique Projections C’est tout!
