How to Calculate Non-Annotative AutoCAD Text Height
To calculate non-annotative AutoCAD text height, you need to know the drawing scale factor, the desired plotted text height, and the location of the multiplication button on your calculator. Follow these steps to calculate the text height:
Determine the drawing scale factor.
Drawing scale is based on the size of the object you’re drawing versus the size of the sheet of paper on which it will be printed.
For example, a house floor plan would have to be scaled down 1:96 (1/8″=1′) to fit an A-size sheet, whereas a watch gear would have to be scaled up 50:1 to appear as more than a dot in the middle of the sheet. As noted, the drawing scale factor is the inverse of the drawing scale: 96 for the house plan, and 1/20 or 0.05 for the watch gear.
You shouldn’t select a scale factor at random. Different industries have lists of preferred (which you should read as mandatory) scale factors, and individual companies in turn may have a short list within the preferred values.
When you edit an existing drawing, it should have a bar scale or text note indicating the drawing scale. If not, and if the drawing dimensions are in model space, you can check the value of the DIMSCALE variable (the system variable that controls dimension scale) or work backwards from existing text sizes.
Determine the height at which notes should appear when you plot the drawing to scale.
Multiply the numbers resulting from Steps 1 and 2.
After you know the AutoCAD text height, you can use it to define the height of a text style or of an individual text object.
If you assign a nonzero height to a text style, all text that you create in that style uses the fixed height. If you leave the text style’s height set to 0 (zero), AutoCAD asks you for the text height every time you draw single-line text objects, which soon becomes a real nuisance.
This discussion of text height assumes that you’re adding non-annotative text in model space. In addition to annotative text in model space, you have a third alternative: Add annotative or non-annotative text to a paper space layout — for example, when you draw text in a title block or add a set of sheet notes that doesn’t directly relate to the model space geometry.
When you create text in paper space, you specify the actual, plotted paper height instead of the scaled-up height.