PyQtGLMeshViewer

A desktop viewer for 3D meshes and point clouds, built with PyQt5 + OpenGL, now including an engineering inspection workbench.

Features

• Supported formats
  • Mesh: .obj, .stl, .ply
  • Point cloud: .ply, .xyz
• Core viewing tools
  • Orbit, pan, zoom
  • Fit view
  • Standard views: Front, Back, Left, Right, Top, Bottom, Isometric
  • Projection toggle: Perspective / Orthographic
• Visual presets
  • Studio Dark
  • Studio Light
  • Blueprint
  • Inspection Lab
• Section tools
  • Interactive section plane
  • Axis switch: X / Y / Z
  • Offset slider with invert direction
• Scene helpers
  • World axes
  • Ground grid
  • Bounding box
  • Model center marker
  • Vertex normals
  • Face normals
• Render controls
  • Mesh surface / wireframe / surface+wireframe
  • Mesh opacity control
  • Point-cloud opacity control
  • Back-face culling toggle
  • Point size and wireframe line width controls
• Desktop conveniences
  • Drag-and-drop file loading
  • Recent files
  • Multiple UI themes
  • Screenshot export to PNG
• Inspection workbench
  • Inspection mode toggle
  • Point / face / measurement item picking
  • Selection highlight and property panel
  • Distance measurement
  • Angle measurement
  • Single-triangle face area measurement
  • Measurement grouping, rename, delete, show/hide
  • Inspection report export as PNG + JSON

Install

pip install -r requirements.txt

Optional but recommended for more robust PLY parsing:

pip install plyfile

Run

Launch the viewer:

python main.py

Open a file directly:

python main.py airplane.ply

Shortcuts

• F / R: Fit view
• W: Toggle mesh wireframe mode
• 1: Front view
• 3: Right view
• 7: Top view
• Ctrl+O: Open file
• Ctrl+S: Export screenshot
• Esc: Close window

Mouse:

• Browse mode
  • Left drag: orbit
  • Right drag: pan
  • Mouse wheel: zoom
• Inspection mode
  • Left click: pick / create measurement
  • Right drag: pan
  • Mouse wheel: zoom

Inspection Workflow

1. Open a mesh or point cloud model.
2. Enable Inspection Mode from the sidebar or Inspect menu.
3. Choose a tool:
   • Select: pick point / face / measurement item
   • Distance: click two points
   • Angle: click three points, with the second point as the vertex
   • Face Area: click one triangle face
4. Use the Groups panel to organize results.
5. Use Inspection Layers to toggle bounding box, center, and normals.
6. Export a report to generate:
   • report_name.png
   • report_name.json

Manual Smoke Checklist

• File loading
  • Open .obj, .stl, .ply, .xyz
  • Drag a file into the window
  • Open a recent file entry
• View behavior
  • Fit view works after loading
  • Front / Right / Top / Isometric switch correctly
  • Perspective / Orthographic toggle keeps navigation usable
  • Section plane clips the model and updates preview immediately
  • Pan stays usable after zooming in closely
• Render tuning
  • Mesh opacity updates immediately and persists across restart
  • Point-cloud opacity updates immediately and persists across restart
  • Back-face culling toggles immediately on meshes
  • Visual preset switches background and lighting immediately
• Inspection mode
  • Select can pick points
  • Select can pick faces on a mesh
  • Empty click does not leave stale state
• Measurements
  • Distance creates one item after two clicks
  • Angle creates one item after three clicks
  • Face Area creates one item after one face click
  • New measurements enter the current group
• Group management
  • Add, rename, delete groups
  • Toggle group visibility
  • Toggle individual measurement visibility
• Geometry overlays
  • Bounding box toggles immediately
  • Model center toggles immediately
  • Vertex normals toggle immediately
  • Face normals toggle immediately
• Export
  • Screenshot export writes a PNG
  • Inspection report writes both PNG and JSON
  • JSON includes model path, timestamp, camera state, groups, and measurements

Project Structure

model-viewer/
├── main.py
├── gui/
│   ├── app_settings.py
│   ├── main_window.py
│   ├── gl_widget.py
│   ├── control_panel.py
│   └── theme.py
├── gl/
│   ├── renderer.py
│   └── camera.py
├── inspection/
│   └── models.py
├── model_io/
│   ├── mesh_loader.py
│   └── point_loader.py
└── math_utils/
    ├── transform.py
    └── trackball.py

Development Check

python -m compileall -q .

Notes

• The current inspection workflow is single-model only.
• Measurement units are reported as model units.
• Face area currently applies to one picked triangle face.
• Measurement groups are session-only unless exported in a report.

License

MIT