fougue/mayo

3D CAD viewer and converter based on Qt + OpenCascade

C++

2,204

1,628 commits

updated Sep 16, 2026

See the code
3d-graphics
3d-viewer
brep
cad
converter
converter-cli
dxf
fbx
gltf
gltf-viewer
iges
meshviewer
opencascade
ply
pointcloud
qt5
step
stl
vrml
wavefront-obj

README

Windows CI Linux CI macOS CI
Downloads Version
Sponsors

Logo

Mayo the opensource 3D CAD viewer and converter

:eyeglasses: Overview

  • Convert 3D files
    Mayo can read/write 3D files from/to STEP, IGES, STL and many other CAD formats

  • Visualize 3D files
    Mayo 3D viewer supports clip planes, exploding of assemblies, measurement of shapes, show/hide parts, ...

  • Cross platform
    Mayo runs on Windows, Linux and macOS

  • Solid foundations
    Mayo is developed in modern C++ with Qt and OpenCascade

For more details have a look at this fine review Introducing Mayo by Libre Arts
There's also a complete video on YouTube

:zap: Features

  • 3D clip planes with configurable capping

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

  • 3D measure tools for circles, angles, lengths, areas, bounding box, ...

  • 3D view cube providing intuitive camera manipulation

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

  • Toggle item visibility within the Model tree(use checkbox)

  • Customizable mesh precision for BREP shapes, affecting visualization quality and conversion into mesh formats

  • Convert files to multiple CAD formats from command-line interface:computer:

:floppy_disk: Supported formats

FormatImportExportNotes
STEP:white_check_mark::white_check_mark:AP203, 214, 242
IGES:white_check_mark::white_check_mark:v5.3
BREP:white_check_mark::white_check_mark:OpenCascade format
DXF:white_check_mark::x:
OBJ:white_check_mark::white_check_mark:
glTF:white_check_mark::white_check_mark:1.0, 2.0 and GLB
VRML:white_check_mark::white_check_mark:v2.0 UTF8
STL:white_check_mark::white_check_mark:ASCII/binary
AMF:white_check_mark::white_check_mark:v1.2 Text/ZIP(export)
PLY:white_check_mark::white_check_mark:ASCII/binary
OFF:white_check_mark::white_check_mark:
3MF:white_check_mark::x:
3DS:white_check_mark::x:
FBX:white_check_mark::x:
Collada:white_check_mark::x:
X3D:white_check_mark::x:
X(DirectX):white_check_mark::x:
Image:x::white_check_mark:PNG, JPEG, ...

See also this dedicated wikipage for more details

:mag: 3D viewer operations

OperationMouse/Keyboard controls
RotatemouseLeft + move
PanmouseRight + move
ZoommouseLeft + mouseRight + move
Zoom +/-mouseWheel(scroll)
Window zoomCTRL + mouseLeft + move
Instant zoomspaceBar
Select ObjectmouseLeft click
Select ObjectsSHIFT + mouseLeft clicks

Mayo supports also multiple 3D viewer navigation styles to mimic common CAD applications(CATIA, SOLIDWORKS, ...)

:package: Install

Release packages are available for Windows and Linux on the Releases page.

Alternatives for Windows:

winget install --id Fougue.Mayo
scoop bucket add extras
scoop install extras/mayo

:hammer: How to build

Instructions for Windows
Instructions for Linux
Instructions for macOS

Easy to use command-line utility for batch conversion of CAD files

Import of glTF file with textures

Import of STEP file with many parts

Import of PLY file defining point cloud

Options dialog with import/export configuration per CAD format

Home page with quick access to recent files

Contributors

HuguesDelorme

1,613 commits

gkv311

4 commits

VictorLamoine

2 commits

luzpaz

2 commits

fougue/mayo

3D CAD viewer and converter based on Qt + OpenCascade

C++

2,204

1,628 commits

updated Sep 16, 2026

See the code
3d-graphics
3d-viewer
brep
cad
converter
converter-cli
dxf
fbx
gltf
gltf-viewer
iges
meshviewer
opencascade
ply
pointcloud
qt5
step
stl
vrml
wavefront-obj

README

Windows CI Linux CI macOS CI
Downloads Version
Sponsors

Logo

Mayo the opensource 3D CAD viewer and converter

:eyeglasses: Overview

  • Convert 3D files
    Mayo can read/write 3D files from/to STEP, IGES, STL and many other CAD formats

  • Visualize 3D files
    Mayo 3D viewer supports clip planes, exploding of assemblies, measurement of shapes, show/hide parts, ...

  • Cross platform
    Mayo runs on Windows, Linux and macOS

  • Solid foundations
    Mayo is developed in modern C++ with Qt and OpenCascade

For more details have a look at this fine review Introducing Mayo by Libre Arts
There's also a complete video on YouTube

:zap: Features

  • 3D clip planes with configurable capping

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

  • 3D measure tools for circles, angles, lengths, areas, bounding box, ...

  • 3D view cube providing intuitive camera manipulation

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

  • Toggle item visibility within the Model tree(use checkbox)

  • Customizable mesh precision for BREP shapes, affecting visualization quality and conversion into mesh formats

  • Convert files to multiple CAD formats from command-line interface:computer:

:floppy_disk: Supported formats

FormatImportExportNotes
STEP:white_check_mark::white_check_mark:AP203, 214, 242
IGES:white_check_mark::white_check_mark:v5.3
BREP:white_check_mark::white_check_mark:OpenCascade format
DXF:white_check_mark::x:
OBJ:white_check_mark::white_check_mark:
glTF:white_check_mark::white_check_mark:1.0, 2.0 and GLB
VRML:white_check_mark::white_check_mark:v2.0 UTF8
STL:white_check_mark::white_check_mark:ASCII/binary
AMF:white_check_mark::white_check_mark:v1.2 Text/ZIP(export)
PLY:white_check_mark::white_check_mark:ASCII/binary
OFF:white_check_mark::white_check_mark:
3MF:white_check_mark::x:
3DS:white_check_mark::x:
FBX:white_check_mark::x:
Collada:white_check_mark::x:
X3D:white_check_mark::x:
X(DirectX):white_check_mark::x:
Image:x::white_check_mark:PNG, JPEG, ...

See also this dedicated wikipage for more details

:mag: 3D viewer operations

OperationMouse/Keyboard controls
RotatemouseLeft + move
PanmouseRight + move
ZoommouseLeft + mouseRight + move
Zoom +/-mouseWheel(scroll)
Window zoomCTRL + mouseLeft + move
Instant zoomspaceBar
Select ObjectmouseLeft click
Select ObjectsSHIFT + mouseLeft clicks

Mayo supports also multiple 3D viewer navigation styles to mimic common CAD applications(CATIA, SOLIDWORKS, ...)

:package: Install

Release packages are available for Windows and Linux on the Releases page.

Alternatives for Windows:

winget install --id Fougue.Mayo
scoop bucket add extras
scoop install extras/mayo

:hammer: How to build

Instructions for Windows
Instructions for Linux
Instructions for macOS

Easy to use command-line utility for batch conversion of CAD files

Import of glTF file with textures

Import of STEP file with many parts

Import of PLY file defining point cloud

Options dialog with import/export configuration per CAD format

Home page with quick access to recent files

Contributors

HuguesDelorme

1,613 commits

gkv311

4 commits

VictorLamoine

2 commits

luzpaz

2 commits

Languages

C++

97.3%

CMake

2.0%