What do you need
Measure one dimension on the model, say the length, and the size you want that same dimension to be. The percent applies to the whole model.
Type a scale percent and see what size the part will actually print.
Print a test cube, measure it, and work out how far off your printer runs. A part that prints small is a negative percent; one that prints large is positive.
Enter the numbers to get the scale.
Scaling changes everything at once, walls, holes and clearances with it. A small percent is fine; for a big resize, edit the model so the walls stay printable. Use one dimension to find the percent, and it scales the whole part the same.
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Three jobs that come up at the slicer, in one place. Resize a model to a size you need and read the percent to type in. Apply a percent and see the size it lands at. Or dial out a printer that comes out a fraction small or large, so the part you pull off the bed is the size you meant.
Resize to a size
Measure one dimension on the model, and say what you want that dimension to be. The percent is the one divided by the other. A 40 mm model you need at 50 mm scales to 125 percent, and because scaling is uniform, every other dimension grows to match. Type the percent into your slicer and the whole part comes out at the new size.
Fixing a printer that prints off-size
No printer is perfect. Filament shrinks as it cools, and a part can land a few tenths of a percent small or large. Print a calibration cube, measure it with calipers, and compare it to the size it should be. That gap is your printer's error. Enter the size you want and that error, and the shrink mode gives you the size to model the part at, so it shrinks or grows back to exactly where you wanted it.
When to scale and when to edit
Scaling moves everything together, which is fine for a small change. Push it far and the walls get too thin to print or too thick to look right, and holes drift out of tolerance. For a big resize, or when a hole has to stay a set size, change it in the model instead, so only what you meant to change does.
More MakerKiln tools
- job cost3D Print Cost CalculatorWorks out what a print actually costs you, down to the power it draws and the failed ones nobody counts.→
- filamentFilament CalculatorTurn filament length into weight or back the other way, by the real density of the material.→
- per hour3D Printer Cost Per HourWhat an hour on the machine costs you, for 11 common printers side by side.→
- resin mixResin Mold CalculatorHow much resin to mix for a mold, with a little spare so you do not come up short.→