To ensure your drawing notes, labels and text are legible it is critical that you adhere to the standards of text heights and scales.
Your drawings are always drawn at full scale in AutoCAD’s model space. This complicates the sizing of text and symbols that are inserted model space must be scaled up. A scale factor can be determined based on the scale that the drawing will be displayed at. Once the scale factor is determined you will also use the value to set the DIMSCALE, and LTSCALE (AutoCAD variables).
For engineering scales the scale factor is the same as the scale. For example, at a scale 1=20 the
scale factor is 20.
To find the scale factor for architectural scales a little algebra is used.
- 1/4″ = 1′ basic scale
- 1/4″ = 12″ convert feet to inches
- 1″ = 48″ multiply both sides by 4
- The scale factor is 48
Text entered into an AutoCAD Model space must take the scale factor into consideration. To
determine the height to enter text into a drawing use the equation or table shown below.
Equation: Drawing Text Height = Plotted Height x Scale Factor
Example: You want the plotted text height text height to equal 0.12″ (almost 1/8″ high) and
you are working at a scale of 1 = 20. Therefore the scale factor is equal to 20.
Drawing Text Height = 0.12 x 20 = 2.4
Note for class work normal text height will be 1/8″ or 12 point font size.
Table 1: Architectural Scale Text Height Table
Table 2: Landscape Architecture and Civil Engineering Text Height Table