Mayo — The Complete Guide: Free Viewing and Conversion of CAD and STEP Files
Mayo is a light, fast open-source (BSD-2-Clause) viewer for 3D files. It is built for a familiar situation: a supplier sent a STEP file, and you need to look at it, measure it and pass it on — without installing a full CAD program.
Mayo
Fougue
3D CAD viewer and converter — STEP, IGES, BREP, STL, glTF and OBJ — with measuring tools and clip planes.
Get it from the vendorWhat you get
- Many formats — STEP, IGES, BREP, STL, OBJ and glTF, plus reading DXF, 3MF and FBX.
- Measuring tools — distances, angles and dimensions directly on the model.
- Clip planes — look inside assemblies and parts.
- Exploded view and view cube — quickly understand how an assembly is built.
- File conversion — from the interface or from the command line for batch conversion.
What to know
Mayo does not edit geometry — it views and converts. Ready-made builds exist for Windows and Linux only; there is no ready build for macOS. Use is free for any purpose, including commercial work.
Related tools
To edit the model — FreeCAD. To clean and repair STL meshes — MeshLab. For quick viewing of many formats — F3D.
FreeCAD
FreeCAD Project
Open-source parametric 3D modeller with workbenches for solid modelling, FEM, drafting and BIM.
Get it from the vendor
MeshLab
ISTI — CNR
Mesh and point cloud processing — hole filling, simplification, alignment and format conversion.
Get it from the vendor
F3D
F3D-APP Foundation
Fast, minimalist 3D viewer — STEP, STL, OBJ, glTF and PLY, including thumbnails in the file manager.
Get it from the vendor
Online 3D Viewer
Online 3D Viewer project
Open STEP, IGES, IFC, STL, OBJ and more in the browser — files are processed locally, not uploaded to a server.
Get it from the vendorThe bottom line
Mayo is a small tool worth having on every workstation: it opens CAD files in seconds, measures and converts — free and open source.