A PDF or image will automatically import at its original scale. It will import into its own layer, and you can use new layers above the import to draw or trace new plans at the same scale.
 
If you want to import a plan and set it to a particular scale in a drawing, you can follow these steps:
  1. Import your PDF.
  2. Have an accurate measurement of a real-world dimension on hand. This will probably already be on your PDF plan, just find a measurement of a wall, door or other space.
  3. Tap the Precision menu and activate Measure.
  4. Activate the Line Guide (the app's real-world ruler), and double-tap the crosshairs at the center. Align the handles to the measured segment on your plan.
  5. Now tap the ratio (1:1) beside Measure in the Precision menu, and enter your real-world measurement into the second field (don't touch the first reference field). When you exit the overlay, you'll see the new scale ratio, 1 : your-new-calculated-value.
The scale will be set for the whole drawing, regardless of how far in or out you zoom. For an illustrated version of these steps, visit our tutorial Scale and Measurement in Concepts. We also have a tutorial on How to Create a Floor Plan that shares how to import a plan and set it to scale, or draw a scaled plan from scratch.
 
You can also exit from a drawing that has your scale pre-set, and either duplicate the drawing or immediately create a new drawing. This duplicate will have the same settings and scale as the last opened drawing. This way, you only have to set the scale one time in one drawing, using it as a type of template.
 
Another way to pre-set a drawing to the scale and tools you want is to set up a project template. Read our tutorial for help on setting up a project template here.