1. Line Types

2. Line Conventions Construction Line: lines used as guides to help draw all other lines and shapes properly. Construction Line

3. Line Conventions Object Lines: used to define parts of the object.. Object Line

4. Line Conventions Hidden Line: Lines used to show interior detail that is not visible from the outside of the part. Hidden Line

5. Line Conventions Center Line: Lines that define the center of arcs, circles. Center Line

6. Border lines Border lines border the edge of the page. Drawn ½” to the edge of the paper. A 2 nd line is drawn for text. Line Conventions

7. Dimension Line Dimension Lines: Lines that are used to contain the dimension. Arrows or slashes are drawn on the ends to show where the dimension line starts and ends.

8. Line Conventions Extension Line Extension Lines: Lines used to show where a dimension starts and stops on an object. Used with dimension lines to properly dimension an object. The extension line does not touch the object. It is 1/16” away.

9. Line Conventions Leader Lines: Leader lines are used to show dimensions of arcs, circles and to help show detail. Leader Line

10. When sketching complex objects, different line types will often overlap each other. Therefore, line precedence must be exercised. Precedence of Lines

11. Rules: Object lines take precedence over hidden and center lines. Hidden lines take precedence over center lines. Cutting plane lines take precedence over all others. Precedence of Lines

12. Object lines take precedence over the hidden lines. An object line here takes precedence over the center line.

13. Precedence of Lines Object lines take precedence over the center lines you would see from the hole. Object lines take precedence over the hidden lines you would see from the slot cut out in top view. An object line here takes precedence over the center line. An object line here takes precedence over the hidden line.