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.
Prerequisites
- A 2D asset you want to print (PNG or SVG)
- Omnvert converter
- A slicer (to verify X/Y/Z in mm)
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
Set width/height in the converter (keep aspect)
Prefer setting real-world size at conversion time so the STL matches mm expectations everywhere. Avoid manually scaling in the slicer unless you have a specific reason.
- 3
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.
- 4
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.
- 5
Account for print tolerances (optional)
If the STL needs to fit with other parts, add clearance. FDM often needs extra tolerance due to line width and material shrinkage. Validate with a small test print before producing a large batch.
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.
Quick verification in the slicer
- Check the imported unit scale (mm) and read X/Y/Z in the object panel.
- Use layer preview to make sure thin features exist on multiple layers.
- If you scale in the slicer, re-check thickness: scaling changes Z too.
If you enter only width (or only height), Omnvert infers the other dimension from the image aspect ratio.