# What's the difference between STL and STEP files?

**STL and STEP are both 3D file formats, but serve different purposes.**

## STL Files (Standard Triangle Language)

**What it is:**

- Mesh-based format (triangles)
- Standard for 3D printing
- Contains only geometry, no history

**Use STL when:**  
✅ Sending to a 3D printer  
✅ Final design, ready to manufacture  
✅ Uploading to print services

**Limitations:**

- Cannot easily edit dimensions
- No parametric history
- Hard to modify after creation

## STEP Files (Standard for Exchange of Product Data)

**What it is:**

- CAD exchange format
- Preserves solid geometry
- Industry standard for manufacturing

**Use STEP when:**  
✅ Importing into Fusion 360, SolidWorks, FreeCAD  
✅ Making modifications to the design  
✅ Need precise dimensions  
✅ CNC machining

**Advantages:**

- Editable in CAD software
- Accurate curves (not triangulated)
- Includes face and edge data

## Which Does Modo Provide?

**Modo generates both:**

- **STL**: Ready for immediate 3D printing
- **STEP**: For users who want to modify designs

## Quick Comparison:

\| Feature \| STL \| STEP \|
\|---------\|-----\|------\|
\| 3D Print Ready \| ✅ Yes \| ⚠️ Needs conversion \|
\| Editable \| ❌ No \| ✅ Yes \|
\| File Size \| Smaller \| Larger \|
\| Accuracy \| Approximated \| Exact \|
\| Best For \| Printing \| Modifying \|

## Workflow:

1. **Just printing?** → Use STL directly
2. **Want to modify?** → Import STEP into Fusion 360 or FreeCAD
3. **After modifications** → Export new STL for printing