Drawing
The True Length
- When a drawing is made without any dimensioning, it can be hard to tell actual length of a side due to projection.
- The true length of a line is its actual length and can be found in an orthgraphic drawing's top and front views.
- Principle lines are lines on the drawing that already give the true length
- These lines can be identified by looking for a line that is:
- a dot/invisible in one view
- parallel to an axes in one view
- The true lengths of the lines are in the other view.
- These lines can be identified by looking for a line that is:
- For a diagonal line, there are many ways to find its true length, but for now we look at the radial method.
- Take a compass, and make the diagonal in one view the "radius"
- Draw horizontal line from one of the end points (Referred to as A) of the diagonal.
- From A, use the compass to draw an arc from the other point(B) to the horizontal line.
- At the point of intersection, draw a vertical line down to the other view.
- Draw a horizontal line from B on the OTHER VIEW to that vertical line.
- Join the point of intersection with point A in this other view.
- This line is the true length of line AB.
- Principle lines are lines on the drawing that already give the true length
page revision: 2, last edited: 11 Oct 2011 09:50