Point, Edge, and Surface Tracking

1. Point, Edge, and Surface Tracking Sections 10.06 and 11.05.03-.04 of Text

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

3. 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 C B C A B B A C A C CLICK

4. 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

5. Point and Edge Tracking 15 17 16 13 14 11 12 8 9 10 2 1 3 4 5 7 6 CLICK

6. 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

7. Surface Tracking 15 17 16 13 14 11 12 8 9 10 2 1 3 4 5 7 6 CLICK

8. 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