How to compare two 3D models side by side
Open a second model next to the first in STL Viewer and compare width, depth, height, volume and triangle count, with the difference for each value.
Compare opens a second model next to the first so you can see the two side by side and check their numbers in one table. Use it to see what changed between two versions of a part, to pick between two downloads of the same model or to check a remix against the original. It is a Premium tool.
Compare two models
- Open the first model. It becomes A.
- Tap Compare in the tools and choose the second file. It opens as B, next to A in the same 3D view.
- Rotate and zoom as usual to look the two models over side by side.
- Read the table: each row shows the value for A, for B and the Difference.
- Tap End comparison to return to the first model alone.
What is compared
| Row | Use it to |
|---|---|
| Width, depth, height | See whether a new version grew, shrank or was scaled. |
| Volume | Compare how much material each version needs. |
| Triangles | See which file is more detailed, or which will slice and load faster. |
When volume is missing
Volumes are shown only for watertight models. If one of the models has holes, open edges or faces pointing inward, its volume can't be measured reliably and is left out. Where the watertight check was skipped, the volume assumes the model has no holes. See Model info for what the watertight check means.
Both models are shown in the same unit. If one was drawn in inches, set its File units first, or the comparison will show a difference of about 25 times.
Ideas
- Before printing an updated part, compare it with the version that already fits to confirm only the intended size changed.
- Comparing two downloads of the same model? The one with far more triangles is finer but heavier for your phone and slicer.
- After scaling and exporting a model, compare the new STL with the original to double-check the sizes.
Premium
Compare is part of Premium, a one-time purchase or a yearly subscription that also unlocks Measure, Section and Scale & export and removes ads.
For a full checklist before you print, read how to check an STL before printing.
Learn more on the blog
- Check Your STL Before Printing: An 8-Point Checklist
- Scale STL to an Exact Size and Measure It (Worked Example)
Questions and answers
Which values does Compare show?
Width, depth, height, volume and the number of triangles for both models, plus the difference between them.
Why is the volume missing for one model?
Volumes are shown only for watertight models. A model with holes, open edges or inward-facing faces has no reliable volume.
Can I compare more than two models?
No. Compare shows two models at a time: the one you opened first and one more.
More guides
- How to open STL, OBJ, 3MF and PLY files on Android
- How to use view modes and gestures in STL Viewer
- How to check a 3D model's size and volume
- How to estimate filament for a 3D print
- How to measure a 3D model in STL Viewer
- How to see inside a 3D model with Section
- How to scale a 3D model and export it as STL
Check your next print on your phone
Free STL, OBJ, 3MF and PLY viewer for Android. Works offline.