PROJECTION SYSTEMS FFD 104 – PARALINE DRAWINGS ORTOGRAPHIC PROJECTION PLANS, SECTIONS, ELEVATIONS OBLIQUE PROJECTION ELEVATION OBLIQUE PLAN OBLIQUE AXONOMETRIC PROJECTION ISOMETRIC DIMETRIC TRIMETRIC PERSPECTIVE PROJECTION ONE POINT PERSPECTIVE TWO POINT PERSPECTIVE THREE POINT PERSPECTIVE

PLAN OBLIQUE (review) FFD 104 – PARALINE DRAWINGS Plan Obliques: In the plan oblique drawing, the plan or top view of the building may be used as the base drawing. In the plan oblique drawing the true size and shape of the building is maintained and can be scaled. In these drawings the plan is rotated usually at 30, 45 or 60 degrees. When drafting a plan oblique, the triangles encourage the use of 45˚- 45˚ and 30˚- 60˚ angles in establishing the orientation of the principal horizontal planes. -We can emphasize one sets of vertical planes over the other or show them to be of equal importance by varying the angles: -In a 45˚- 45˚ plan oblique, both principal sets of vertical planes are emphasized equally, -In a 30˚- 60˚ plan oblique, one principal sets of vertical planes receive more emphasis than the other,

AXONOMETRIC DRAWINGS FFD 104 – PARALINE DRAWINGS Isometric Projection: It is an axonometric projection of a three-dimensional object inclined to the picture plane in such a way that its three main axes make equal angles with the picture plane and are equally foreshortened. Dimetric Projection: It is an axonometric projection of a three-dimensional object in which two of the main axes are equally foreshortened and the third appears longer or shorter than the other two. Trimetric Projection: It is an axonometric projection of a three-dimensional object in which all three main axes are foreshortened at a different rate. Of these three the most commonly used in drawing is isometric projection. - All three axes receive equal emphasis. - All axial lines are drwan to true length at the same scale

ISOMETRIC DRAWING FFD 104 – PARALINE DRAWINGS All three visible surfaces have equal emphasis - The angle of view is slightly lower than that of obliques - Orthographic plans and elevations cannot be used as base drawings. To construct an isometric drawing, first establish the direction of the three principal axis. Since they are 120 degrees apart on the picture plane, if we draw one axis vertically, the other two axes make a 30 degree angle with a horizontal on the drawing surface.

CIRCLES IN PARALINE DRAWING FFD 104 – PARALINE DRAWINGS CIRCLES IN PARALINE DRAWING Circles in non-frontal planes in paraline drawings appear as ellipses. With the four center method (using two sets of radius with a compass or a circle template) you can approximate an ellipse that is usually close enough to a true ellipse to suit most purposes. CONSTRUCTION: - Draw circumscribing square axonometrically - At the mid-points of the sides of the axonometric square, draw perpendiculars and extend them until they intersect. - With these points of intersection as centers, and with r1 and r2 defined by the distance between the intersection and the perpendicular corner, describe two sets of arcs in equal pairs between the points where perpendicular lines originate.