Point, Edge, and Surface Tracking Sections 10.06 and 11.05.03-.04 of Text I think this stuff is too advanced for this point in time with the students. It should probably be moved back to the part with the missing views.

Objectives Use the principles of orthographic projection to identify points, edges, and surfaces in orthogonal views.

Points in Orthographic Projection When views of an object are projected onto the glass cube and it is unfolded, points will “line up” from one view to the next. B A B C C A B B A C A C CLICK

Edges in Orthographic Projection Edges on objects are defined by two or more points, so they also project orthographically between views. Note that sometimes, an edge may appear to be a point, when you are looking directly down the line. CLICK

Point and Edge Tracking 17 16 15 No. Front Top 1 Edge 1-2 8-9 or 17-16 2 Point 3 12 or 13 2-4 9-10 or 16-15 4 3 or 6 12 5 1 or 7 17 6 10-11 or 14-15 7 9-16 13 14 11 12 8 9 10 1 2 3 4 CLICK 7 6 5

Surfaces in Orthographic Projection Surfaces on objects are defined by three or more points, so they also project orthographically between views. Note that sometimes, a surface may appear to be a line, when you are looking directly down the edge of that surface. CLICK

Surface Tracking Surface No. Front Top 17 16 15 13 14 11 12 8 9 10 1 2 2-3-4 9-10-11-12-13-14-15-16 2 Surface 2 3-6 12-13 3 Surface 3 1-2 8-9-16-17 4 Surface 4 4-5 14-15 5 Surface 5 3-4-5-6 12-11 or 13-14 6 Surface 6 1-2-4-5-7 8-9-10 or 17-16-15 7 Surface 7 1-7 8-17 17 16 15 13 14 11 12 8 9 10 1 2 3 4 CLICK 7 6 5

Point, Edge, and Surface Tracking Use this time to practice sketching orthographic projections of more complex objects. Don’t forget to include hidden lines and centerlines. In class assignment