# fougue/mayo

3D CAD viewer and converter based on Qt + OpenCascade

Repository: https://github.com/fougue/mayo
Canonical: https://ross.abutalabs.com/products/mayo
Language: C++
License: BSD-2-Clause
License Family: permissive
Topics: cad, opencascade, iges, step, brep, stl, 3d-viewer, 3d-graphics, wavefront-obj, meshviewer, gltf, gltf-viewer, vrml, qt5, converter, converter-cli, dxf, ply, pointcloud, fbx
Last push: 2026-08-26T13:55:16+00:00

## Health v2 (maintenance only)
Score: 85/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 99, release rhythm 59, longevity 100
- inputs: {"age_days": 3687, "days_push": 7, "days_rel": 61, "gap_med": 535, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2132, forks 351 (observed 2026-08-28T04:06:17.274291+00:00)

## What it is
Mayo is an open-source 3D CAD viewer and converter built with Qt and OpenCascade in modern C++. It visualizes CAD models with measurement, clipping, and assembly exploration tools, and converts between formats like STEP, IGES, STL, OBJ, glTF, and DXF via GUI or CLI.

## Use cases
- view STEP and IGES CAD files on Linux
- convert STL files to STEP format
- measure lengths and angles in a 3D model
- explode an assembly to inspect individual parts
- batch-convert 3D files from the command line
- preview glTF and OBJ meshes with clip planes
- open DXF files without a full CAD suite

## When to choose
- you need a lightweight free CAD file viewer across Windows, Linux, and macOS
- you want scriptable conversion between major 3D/CAD formats
- you need measurement, clipping, or assembly exploration without a heavy CAD package

## When to avoid
- you need parametric modeling or CAD editing rather than viewing and converting
- you require drawing/2D documentation generation
- you need a web-based or embedded 3D viewer

## Facets
- artifact type: application
- maturity: active
- function: gui, cli, image-processing, graphics
- domain: graphics, files, cross-platform
- platform: windows, cpp
- tags: cad, 3d-viewer, file-converter, opencascade, step, iges, stl, mesh, gltf, dxf, computer-aided-design, linux, macos, qt

## Member repositories
- fougue/mayo (main) score 85

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:17.274291+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T02:52:01.764302+00:00, confidence not recorded.
  - readme: https://github.com/fougue/mayo (fetched 2026-08-28T04:06:17.274291+00:00, sha 28d40f90bf1f)
- Data as of 2026-08-30T08:39:29.467469+00:00.