Many new users of Civil 3D, as well as users migrating from Land Desktop, have questions about the best practices for controlling Civil 3D label scales and annotative text scales. Although they function similarly in many ways, there are important differences. This article is intended to provide clarity on scale control settings by summarizing the similarities and differences between these methods of annotation.
First, we will consider Civil 3D labels. In model space they are scaled based upon the text height setting in the controlling label style, as well as the annotative (drawing) scale. For example, if the text height in the label style is set to 0.1000” and the annotative scale is 1” = 50’, the actual text height in model space will be 0.1000 (the text height) multiplied by 50 (the annotation scale), or 5’ (as demonstrated in the images below).
However, in paper space, label text always appears at the same height regardless of the viewport scale or zoom level. Label styles in which the text height is set to 0.1000” will appear at a height of 0.1000 inches in paper space, even if displayed in viewports set at different scales. In the image, below, the left viewport is set to 1” = 100’ and the right viewport is set to 1” = 50’. Although the model is at different scales, the alignment labels still display at the same text height, 0.1000 inch, as presented in the second image below.
Note: To ensure that Civil 3D object linetypes also display and plot properly, we recommend setting the MSLTSCALE, PSLTSCALE, and LTSCALE system variables to 1.
Next, we will consider annotative text, an AutoCAD element. Text styles are made annotative by selecting the Annotative option and setting a Paper Text Height in the Text Style dialog, when they are created or modified (see image below).
Making a text style annotative locks the height of text in a paper space viewport to the value established in the Text Style dialog Paper Text Height box, regardless of the viewport scale. This is analogous to setting a Civil 3D label’s text height in its label style. Just as the Civil 3D labels, shown above, the annotative MTEXT displays at the same height, even though the viewports are set to different scales. This can be seen, in the image below, where two side-by-side viewports display the same annotative text. Although the viewports are set to different scales, 1” = 100’ and 1” = 50’, the annotative text is displayed at the same size in each.