Introduction to Engineering 2-D & 3-D Coordinate Systems Sketching - 7

Coordinate Space in 2-D X -X -Y Y A 2-D coordinate system locates the origin at the intersection of the X axis (horizontal axis or abscissa) and the Y axis (vertical axis or ordinate). These are called View Coordinates. Sketching - 7

Determine the Coordinates -3 6 -3 -2 6 -2 0 2 D B C Sketching - 7

Coordinate Space in 3-D Z In the 3-D coordinate system the axes are mutually perpendicular, and the origin (0,0,0) is usually taken at the intersection of these axes. Y -X In many math books (where students have seen 3-D coordinate axes before) the X and Y axes are in the plane of the text book page, and the Z axis goes into the next page. For engineering drawings, we assume tat the person looking at the object will be looking fown on a tabletop. Thus, the X and the Y axes are in the plane of the tabletop and the Z axis goes in and out of the table. This is the convention used by the CAD software also. -Y X -Z Sketching - 7

Coordinates for the 3 Views and Isometrics Task: Using the world coordinates convention for computers and CAD, determine the values of the coordinates for points in multi-view drawings and isometric drawings. Note the Origin (0,0,0) can be set at an arbitrary point. X Z Y Sketching - 7

World Coordinates in the 3 Views B C D Y X A 0 0 0 A X Y Z Note C to D is a straight line. Note some students may find it easier to do the isometric for visualization and then do the coordinates. Encourage students to do it the way that works for them. 3 5 5 Z X Z Y 4 1 2 7 1 0 Sketching - 7

World Coordinates in the Isometric B B A X Z Y C D Y X A 0 0 0 A X Y Z 3 5 5 Z X Z Y 4 1 2 7 1 0 Sketching - 7

Assignment #14 Assignment Isometric & Coordinates handout in Assignment Packet Sketching - 7