Printing CAD drawings: PDF settings, line weights and scale

The most common problems with CAD plots are not mysterious. The page was set to the wrong size, the file was scaled to fit, or the thinnest lines turned out lighter than expected. All of them are preventable at the export stage. Here is a simple routine.

Step 1: Set the sheet size to match the real sheet

Before you export, check the page setup in your layout tab. The sheet should be the real size you want printed, such as ARCH D (24 x 36 inches) or ANSI C (17 x 22 inches). If you are not sure which sizes exist, our drawing sizes guide lists them all.

Choose a paper size that matches the sheet exactly. If you pick a nearby size and rely on the software to shrink it, your scale will no longer be correct.

Step 2: Export from the layout, not model space

Set up the viewport in a layout with the scale defined, such as 1:50 or 1/4 inch = 1 foot. Then export or print that layout to PDF. Exporting straight from model space often produces a scale that depends on whatever the window happened to show.

Step 3: Use true scale, never 'fit to page'

In the plot or print dialogue, set the scale to 100 percent or the exact scale the layout uses. If the option says 'fit to page', 'shrink to fit' or 'scale to paper', turn it off. Fit to page makes a different scale every time the margin or sheet changes, and the result is a drawing that cannot be measured.

The same rule applies in the PDF viewer. When someone opens your PDF and prints it, they should choose 'actual size' or 100 percent.

Step 4: Keep the drawing as vector

A PDF can hold two kinds of content. Vector lines and text stay crisp at any size. Raster content, such as a pasted screenshot or a flattened image, goes soft when enlarged. Export your drawing as a vector PDF rather than as a picture of a drawing. If a scanned image or photograph is included, make sure it is high enough in resolution on its own.

Step 5: Check line weights and colours

Line weight is what makes a plan readable. As a general approach:

• Use heavier lines for cut edges, walls and outlines
• Use medium lines for objects and details
• Use light lines for dimensions, hatches and grids
• Avoid hairlines (zero weight) unless your plot style defines how they print

Colours can be mapped to line weights through a plot style table. If the drawing is meant to be black and white, set all colours to black, because light yellows and cyans can nearly disappear on paper. If you are sending a coloured drawing, say so, so we do not assume it is monochrome.

Step 6: Fonts and text

Embed fonts when you create the PDF. If you are exporting a text-heavy plan, open the finished PDF and zoom to the smallest note to check that it is readable. Small text under about 1/16 inch tall in the final print is hard to read on site.

Step 7: Verify the scale with a scale bar

Add a graphic scale bar to each sheet. After exporting, open the PDF, measure the bar with the measuring tool and compare it to a known dimension. If the bar is right, the sheet is right. A scale bar is also the safety net when drawings get reduced, because it shrinks with the page.

Step 8: Send your files cleanly

• One PDF per sheet, or a single multi-page PDF in sheet order
• A clear file name, for example A101-Floor-Plan-R2.pdf
• Note the sheet size, paper type and number of copies in your message
• Include the original CAD files only if we have asked for them

You can email your files with a quote request or ask us for help if a file will not export properly. We print engineering prints and blueprint-style plans for Oakville, Mississauga and Burlington customers, and ship across Canada and the USA. If you are comparing how pricing works, our blueprint printing cost guide explains the factors. Contractors may also like our overview of printing for contractors and architects.