Apr 07, 2026beginner • 7 minstl · scaling · thickness · units · 3d-printing
Scaling and Thickness: Getting Real-World Dimensions in STL
How to set width/height in millimeters, keep aspect ratio correct, pick a print-safe thickness, and validate dimensions before slicing.
Step-by-step
- 1
Decide the target size (mm)
Start from a real requirement: a 40 mm keychain, a 120 mm sign, etc. Pick width OR height — the other dimension follows the aspect ratio.
- 2
Pick a thickness that prints reliably
For flat logos, 1.6–3.0 mm is a good range. If you need rigidity, increase thickness or add a backing plate in your design.
- 3
Convert and verify dimensions
Generate STL with the PNG / SVG → STL converter. Then check the model’s size in your slicer (X/Y/Z). If it’s off, adjust width/height and reconvert.
Common scaling mistakes
- Setting both width and height manually and accidentally squashing the aspect ratio.
- Using ultra-thin thickness (<1 mm) for FDM prints, causing warping or fragile parts.
- Ignoring Z in preview — thickness is your Z dimension.
Converter shortcut
If you enter only width (or only height), Omnvert infers the other dimension from the image aspect ratio.