My imported drawing is the wrong size. How do I scale it to match a real measurement?

Why it happens

Imported vectors are read in at the size and scale they had in the original program. If that program worked in different units, or the artwork was a trace of a picture, the numbers will not match the real object. The cure is to measure one feature whose true size you know, then scale the whole design by the ratio.

Steps

1. Open the Measure tool and choose Measure Between 2 Points.
2. Click the two ends of a feature you know, such as two hole centers or the ends of an edge. Read the Distance. For a single straight edge you can use Span / Contour Properties instead and read its Length.
3. Select the entire design. Selecting everything keeps all parts in proportion to one another.
4. Open Set Size (the shortcut T opens it in interactive mode).
5. Set the mode to Scale selection so the selection is scaled as one group, and check Link XY so width and height stay in proportion.
6. In the width box, type the current width times the true size divided by the measured size, then press the equals key. Number boxes do the math for you. Example: the box shows 10.4, the feature should be 4 but measured 3.82, so type 10.4*4/3.82=.
7. Apply, then measure the same feature again to confirm.

Shortcut for a units mix-up

If the drawing was made in millimeters and your job is in inches, every size is 25.4 times too large. The number boxes have conversion letters: I converts a millimeter value to inches (25.4i= gives 1) and M converts inches to millimeters (2M= gives 50.8). Type the current width followed by i= or m= with Link XY checked.

Pro tips

• Pick the longest known dimension you have. A small measuring error matters less over a long distance.
• The Anchor setting decides which point of the selection stays put while it resizes. Choose a corner that is already where you want it.
• Scale items individually resizes each object about itself and breaks the layout. Use it only when you mean to.
• If 3D components are in the selection, Auto Scale Z decides whether their height changes with them.