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

- a
- 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.

page revision: 2, last edited: 11 Oct 2011 09:50