MULTIVIEW DRAWINGS - 1
Picture plane (paper or computer screen) 3-D object View point Lines of sight 2-D projection Engineering graphics are obtained by projection from the 3-D object to the viewing surface (the picture plane)
GL2:3 • Perspective projection is rarely used in manual drawing Types of projection • Rather, we us a variety of orthographic projections, for which the projection rays are parallel
Picture plane (paper or computer screen) 3-D object View point at In orthographic projection, the projection rays are parallel (view point at infinity) Parallel lines of sight 2-D projection
Perspective vs. Parallel Projection PERSPECTIVE PROJECTION Object is positioned a finite distance from the viewer and is viewed from a single point. ◦ Lines of sight are converging, not parallel ◦ Mimics human eye behavior PARALLEL PROJECTION Object is positioned at an infinite distance and viewed from multiple points. ◦ Lines of sight may be perpendicular to plane of projection (orthographic) or inclined relative to the plane of projection (oblique)
Classification of Projections: Each classification of projection has a particular purpose from production use…to technical illustration.
Projection types: Projection type is defined by the “line of sight” from the observer. We will see Axonometric and Oblique projections more in a later chapter
Let’s now look at multiview drawings in more detail…..
Multiview Projection See Fig. 10.1 to locate the multiview projections in the taxonomy of projections: Projection Parallel projections Orthographic projections Multiview projections Line of sight Projection plane Object
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- Spring '14
- Map projection, Orthographic Projection, Parallel projection, Graphical projections, Multiview Drawings, oblique projection