STL vs OBJ: Which Format Should You Export?
FreeTextToCAD exports your models in two formats: STL and OBJ. Here's exactly when to use each one.
STL: The 3D Printing Standard
STL (STereoLithography) is the most widely supported format in the 3D printing world. Every major slicer — Cura, PrusaSlicer, Bambu Studio, IdeaMaker, Simplify3D — opens STL files. It stores a mesh as a list of triangles with no color, material, or UV information.
FreeTextToCAD writes binary STL, which is the format you should use for 3D printing 99% of the time. Binary STL is compact, fast to load, and universally supported. A model with 100,000 triangles takes about 5MB as binary STL — roughly 5–6× smaller than the human-readable ASCII variant, which we don't emit.
OBJ: For CAD Software and Rendering
OBJ is a more feature-rich format that supports face normals, UV coordinates (texture mapping), and material references. For AI-generated CAD models, the extra features rarely matter, but OBJ is a better choice when:
- You're importing into Blender, Maya, or Cinema 4D for further editing or rendering
- You're importing into Fusion 360, FreeCAD, or other CAD software for modification
- You need to share the model with someone using non-printing 3D software
Compatibility Quick Reference
- Cura / UltiMaker: STL ✅, OBJ ✅
- PrusaSlicer: STL ✅, OBJ ✅
- Bambu Studio: STL ✅, OBJ ✅
- Blender: STL ✅, OBJ ✅
- Fusion 360: STL ✅, OBJ ✅
- Tinkercad: STL ✅, OBJ ❌
- Meshmixer: STL ✅, OBJ ✅
Recommendation
For 3D printing: use STL. It's smaller, faster, and universally supported. For everything else — remixing, rendering, or CAD import — use OBJ.
Once you have your file, load it into your slicer, check the model looks correct, set your print settings, and slice. See our guide on preparing your AI CAD model for printing for slicer-specific tips.