Here are some key things students should remember when using object lines in technical drawings:

• Line Weight Matters

• Object lines should be the boldest, most visible lines in your drawing

• Keep line weight consistent throughout the drawing

• Press firmly enough to make dark, clear lines but not so hard that you damage the paper

2. Make Clean Lines

• Use a ruler or straight edge for straight lines

• Draw lines in a single, smooth motion

• Avoid going over lines multiple times, which can make them look messy

• Lines should meet exactly at corners without overlapping or gaps

3. Line Priority

• Object lines take priority over other line types at intersections

• When object lines cross other lines (like hidden or center lines), the object line should be continuous

• Keep object lines solid - never broken or dashed

4. Show Only What's Visible

• Object lines represent edges and surfaces you can see directly

• Don't use object lines for hidden features (use hidden lines instead)

• Think about what you would actually see if you were looking at the real object

5. Line Sequence

• Draw horizontal lines from left to right

• Draw vertical lines from top to bottom

• This helps maintain consistent line quality and reduces smudging

6. Common Mistakes to Avoid

• Don't make lines too light - they should stand out clearly

• Avoid freehand drawing when straight lines are needed

• Don't leave gaps or overlaps at corners

• Make sure all object lines have the same thickness

Practice Challenge

On a piece of graph paper please freehand sketch the following line designs as accurately as possible - meaning, count the boxes and create the EXACT same design on your graph paper.  Do your own design in the last 2 boxes.

Reflection

"When you're drawing an object with many edges, how do you decide which lines should be object lines?"

"What challenges did you face when trying to make consistent object lines, and how did you overcome them?"

"What do you need to work on when drawing object lines?"

"What might happen if object lines weren't drawn correctly in a technical drawing?"