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About the developer

279 Stars 95 Forks BSD 2-Clause "Simplified" License 782 Commits 18 Opened issues


3D CAD viewer and converter based on Qt + OpenCascade

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What is Mayo

Mayo is a 3D viewer and converter inspired by FreeCad


  • View and convert 3D files in different formats
  • Explore assembly trees and view properties
  • Cross platform: runs on Windows, Linux and macOS
  • Underlying toolkits: OpenCascade and Qt

Current features

  • Support of multi-documents, user can open many files in the session
  • Support of STEP/IGES assemblies(product structure and colors)
  • Area and volume properties for meshes and shapes
  • Editable name of STEP/IGES entities

  • Editable 3D properties of the imported items, eg. material, color, display mode, ...

  • 3D exploding of the model tree, allowing better exploration of complex designs

  • 3D clip planes with configurable capping

  • 3D view cube providing intuitive camera manipulation

  • Perspective/orthographic 3D view projection

  • Save image(snapshot) of the current 3D view

  • Quick access to the CAD files recently open thanks to thumbnails in the Home page

  • Toggle visibility of any item from the Model tree(use checkbox)

  • Customizable precision of the meshes computed from BRep shapes, affecting visualization quality and conversion into mesh formats

  • Convert files to multiple CAD formats from command-line interface(CLI)

3D viewer operations : * Rotate : mouse left + move * Pan : mouse right + move * Zoom : mouse wheel(scroll) * Window zoom : mouse wheel + move * Instant zoom : space bar * Select Object: mouse left click * Select Objects: SHIFT + mouse left clicks

Supported formats


Import Export Notes
STEP AP203, 214, 242(some parts)
IGES v5.3
OpenCascade BREP
OBJ Requires OpenCascade ≥ v7.4.0
glTF Import requires OpenCascade ≥ v7.4.0
Export requires OpenCascade ≥ v7.5.0
Supports 1.0, 2.0 and GLB
VRML v2.0 UTF8
STL ASCII/binary
AMF v1.2 Text/ZIP
Requires gmio ≥ v0.4.0


How to build Mayo

Build instructions for Windows MSVC
Build instructions for Debian

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