3D File Formats Explained

Which File Format Should You Use?

If you're sending a 3D model for printing, the format matters. Here's a quick rundown of the most common ones and when to use each.

STL — The Standard

Use when: You have a finished model and just need it printed.

STL (Standard Tessellation Language) is the most widely used format for 3D printing. It stores the surface geometry of your model as a mesh of triangles.

Pros: Universal compatibility, simple, lightweight Cons: No colour/texture data, no unit information, can't be easily edited

3MF — The Modern Choice

Use when: You want a better STL with extras.

3MF is a newer format designed specifically for 3D printing. It includes units, colour, material info, and multiple parts in a single file.

Pros: Preserves units and metadata, smaller file size, multi-part support Cons: Not as widely supported by older tools

STEP — The Engineer's Pick

Use when: You want me to modify or adjust the design before printing.

STEP files preserve the parametric data from your CAD tool, making them easy to edit. If you need design changes, this is the best format to send.

Pros: Editable, precise, industry standard for CAD exchange Cons: Larger files, requires CAD software to open

OBJ — The Visual One

Use when: Your model includes textures or vertex colours.

OBJ files can include colour and texture data, making them useful for visual models. For functional prints, STL or 3MF is usually better.

Quick Reference

How to Export

• Fusion 360: File → Export → choose STL, STEP, or 3MF
• SolidWorks: File → Save As → choose format
• Blender: File → Export → STL or OBJ
• TinkerCAD: Export → STL or OBJ
• OnShape: Right-click part → Export → STEP or STL

Not Sure?

Just send whatever you have. I accept all common formats and can convert between them. If your file needs fixing, I'll sort it out. Get in touch.