Online STL Viewer — 3D Model & Print Checks
See your model. Find possible print problems. Preview the finish before you make it.
Example model — try the controls or add your own file.
Your print setup
STL and OBJ do not declare units. Confirm the scale; 3MF uses its declared unit.
Settings changed. Apply and recheck to update the model and findings.
Product look
An illustrative render. Color, gloss and layer lines will differ on a real printer.
STL saves the applied size and orientation, in mm. Original files are unchanged. Color and material are only in the preview.
Print layers
Add G-code generated by your slicer to see actual extrusion paths. Model cross-sections alone are not sliced print paths.
Linear G0/G1 extrusion paths only. No printer commands are executed. This is a path view, not a thermal or physical simulation.
Save image (PNG)
STL saves the applied size and orientation, in mm. Original files are unchanged. Color and material are only in the preview.
What to check next
Checks help you inspect geometry; they do not certify printability, strength, fit or watertightness of the physical object. Self-intersection detection, mesh repair and slicing are not included.
Start with FDM filament prints. Match units, nozzle and build volume to your printer. Supports, adhesion, material and machine settings still need a slicer and a test print.
Desktop: 25 MB / 150,000 triangles. Small screens: 10 MB / 60,000 triangles. G-code: up to 450,000 / 180,000 total segments. 1 MB = 1,000,000 bytes.
Rendering happens only when needed. Large files may be slower on phones.
Libraries and licenses
Three.js · MIT · fflate · MIT
The MIT License Copyright © 2010-2026 three.js authors Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. MIT License Copyright (c) 2026 Arjun Barrett Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Open an STL file without installing a viewer
Choose an STL, OBJ or supported core 3MF file to rotate the model and check its dimensions. Review mesh edges, sampled thin walls and possible overhangs before returning to your CAD or slicer. Files stay on your device; no account is needed.
Is this a slicer or a strength test?
These are geometric checks, not a strength or stiffness calculation. Wall thickness is sampled and approximate. The viewer does not repair meshes or slice models. A sliced G-code file can show supported linear extrusion paths; print success is not guaranteed.