Engineering Scales collects practical CAD plotting guidance for this topic within Scale & Viewports. Use these articles for setup, verification, troubleshooting and reliable final output.
Engineering scales express paper inches against model feet, for example 1″=20′ or 1″=50′. They are common in civil and site work. Set the scale on the viewport, not by shrinking the model.
For a drawing that uses decimal feet, 1″=20′ means one inch on paper represents twenty feet in the model. Select the named engineering scale in the viewport, lock it, and verify a known distance.
At 1″=50′, one inch on paper represents fifty feet in the model. This scale is common for larger site or civil views. Apply it to the viewport and verify the PDF before issue.