Scaling Drawings - Step By Step

Okay, I’ve often wondered how to do this in the past. It used to be a trial and error process until I got an enlargement or reduction that was close enough. But I decide to finally learn how to do it. One of the first resources I ran into was Paul Budzik’s video on his YouTube channel “Scale Model Workshop”. His video details the approach using CorelDraw if I recall. I didn’t have CorelDraw but I did have Inkscape which is a free drawing program.

The steps shown here are a document I put together for myself to refer to each time I need to do this. The directions refer to the Inkscape program but the general approach should work for other drawing programs. I also refer to Silhouette Studio which is a graphics program for the Silhouette Portrait and Cameo vinyl cutters. This tool is great for making masks. You could also use this approach for the Cricut vinyl cutter, but I do not know the name of the software for that machine.

Hope someone can find this useful.

Scaling And Using Drawings

  1. Purpose: Instructions for importing a drawing into Inkscape and then scaling it to the desired scale of the model for the purposes of measuring and getting shapes.
  2. To make finding these drawings easier in the future, the plan is to store them in a folder in the aviation folder under the appropriate aircraft . The folder will be named “Scaled Drawings” The original drawings will be stored in a folder named “Blueprints” in the same aircraft folder.

At the end of this document are suggested uses of this capability

Directions for scaling the drawing

  1. Open Inkscape and set document horizontal and vertical widths to larger than the desired size of the drawing.

  2. Depending upon the final scaled size of the drawing, it may not fit on a standard size piece of paper.

  3. This is probably easier if the page size is set initially to standard page sizes (i.e. 8.5 x 11 inches)

  4. This is accomplished in File → Document Properties

  5. Depending upon the orientation of the drawing, it may be desirable to change from portrait to landscape or vice versa

  6. Make sure the document is displayed in inches as well

  7. Import the drawing or scan into Inkscape

  8. Note that scans should be done at 600 DPI to get best detail

  9. If the drawing is larger than the page size (it probably will be). Then use Object → Transform → Scale (or drag a corner using CTRL) to resize the imported drawing to a size that fits inside the paper size.

  10. It is important to keep the proportions locked when resizing.

  11. Using the layers window, rename the layer to “Scan” or “Original” and lock it

  12. Create a new layer above and call this “Above Scan” or “Above Original”

  13. This is necessary in order to allow you to draw a rectangle without moving the imported drawing around

  14. Find something on the drawing of a known dimension, preferably something that has a measurement shown on the drawing, but a known dimensioned object can be used

  15. Make sure that Inkscape is set to use inches rather than millimeters

  16. Draw a rectangle in the “Above Scan” layer that exactly matches the width of the known object.

  17. Or draw the rectangle to a known size. For example 2 inches.

  18. Using a calculator convert the known dimension of the object to inches and then divide by the scale (i.e. 48, 72, etc)

  19. This yields the scaled dimension in inches of the object when scaled to the desired scale

  20. For example Known dimension of the object is 575.66929

  21. 575.66929 / 48 = 11.993

  22. Scaled dimension (in inches) in 48th scale is 11.993 inches

  23. In the information bar copy the actual width of the rectangle dimension in inches

  24. Divide the scaled dimension of the rectangle by the actual dimension

  25. For example , actual dimension of rectangle is 8.902 inches

  26. 11.993 / 8.902 = 1.347

  27. The scale factor is 1.347

  28. This gives you the scale factor to reduce or enlarge the drawing

  29. Switch to the “Scan” or “Original” layer in Inkscape and unlock this layer

  30. Zoom out and select the entire imported drawing. Copy the actual width (in inches) of the selected drawing from the information bar

  31. For example width is 11 inches

  32. In the calculator, multiply the entire drawing width by the scale factor

  33. For example 11 * 1.347 = 14.820 inches

  34. This gives you the desired width of the drawing to have it scaled to the desired scale (i.e.48th scale)

  35. In Inkscape, change the entire drawing width dimension to this desired width and hit the ENTER key

  36. The drawing should resize to the correct scaled size.

  37. Lock the scan layer and remove the “Above Scan” layer

  38. Save the drawing.

Suggested Uses Of The Scaled Drawing

At this point, you can print the drawing if needed. This is useful for creating paper camouflage masks for airbrushing. Or comparing the drawing to the actual model for accuracy. Or laying out rivet and panel lines.

Or add a “Dimension” layer above the “Original” layer, and measure parts of the drawing by drawing rectangles and reading out the size from the information bar. This will give you the scale dimension of parts you may wish to duplicate

You can also select portions of the drawing and copy them to another drawing and print it if a shape is needed

Note that this can also be used to create drawings than can be exported and imported into Silhouette Studio for the purposes of making masks or for making and printing decals