Line Conventions
Line Conventions Lines of varying style and thickness used communicate an object’s geometry.
Line Conventions Used in technical drawings Technical Drawings – Detailed drawings that contain all the information necessary to produce the part.
Construction Line Very lightly drawn lines used to define size and shape.
Object Line Thick and dark Define the object
Hidden Line Show interior detail not visible from the outside of the part
Center Line Define the center of arcs, circles, or symmetrical parts Half as thick as an object line
Section Line Define where material is cut away
Short-Break Line Freehand drawn line Presentation Name Course Name Unit # – Lesson #.# – Lesson Name Short-Break Line Freehand drawn line Shows where part is cut away to reveal internal detail
Dimension Line Shows distance Arrows on ends to show start and end Presentation Name Course Name Unit # – Lesson #.# – Lesson Name Dimension Line Shows distance Arrows on ends to show start and end Actual distance is located in the middle
Extension Line Shows where a dimension starts and stops Presentation Name Course Name Unit # – Lesson #.# – Lesson Name Extension Line Shows where a dimension starts and stops Line starts 1/16” away from part to avoid confusion with object lines
Long-Break Line Shorten very long objects when geometry is uniform Presentation Name Course Name Unit # – Lesson #.# – Lesson Name Long-Break Line Shorten very long objects when geometry is uniform
Leader Line Show dimensions of arcs, circles and detail Presentation Name Course Name Unit # – Lesson #.# – Lesson Name Leader Line Show dimensions of arcs, circles and detail
Precedence of Lines Complex drawings may require different line types that overlap.
Precedence of Lines Examples Object line has precedence over hidden lines Object line has precedence over center line
Rules of Line Precedence Object lines take precedence over hidden and center lines Hidden lines take precedence over center lines Cutting plane lines take precedence over all others