OpenPara

Features

What is in OpenPara today.

Parts

  • 2D sketches with a constraint solver and dimensions
  • Extrude, cut, revolve, sweep (including twisted sweeps) and loft, each as a boss or a cut
  • Fillet, chamfer, patterns, mirrors, reference planes and axes
  • Named variables (Globals), formulas and configurations
  • One program-wide unit system: mm, cm, m, in, ft, N, kN, kip and more

Part Generator

  • Spur, helical, herringbone and internal ring gears with true involute teeth and exact tooth counts
  • Size by module, diametral pitch, pitch diameter or outside diameter; optional profile shift, backlash and bore
  • Gear trains of up to three gears, sized from centre distances, ratios or tooth counts
  • Planetary sets (sun, planets, ring) with valid planet counts and the ratios for each way of holding them
  • Each gear opens as its own part. OpenPara gives you the centre distances and turn angles; you build the assembly

Assemblies

  • Mates, sub-assemblies and patterns
  • Variables of their own
  • Positions, mate values and pattern spacing can be formulas

Simulation

  • 1D beam and frame analysis
  • 2D finite-element analysis and 2D flow
  • Results you can slice and inspect

Renderer

  • Sun and sky from a date, time and place
  • Spot light, floor and several cameras
  • Still pictures and MP4 videos, using Mitsuba 3

Open source

  • GPL-3.0 licensed
  • Built on build123d (OpenCascade), PyQt6, pyvista / VTK, gmsh and Mitsuba 3
  • All the code is on GitHub
Honest limits

What is checked, and what is not

We would rather tell you than have you find out.

  • The gear geometry is checked against textbook values and against the real solids: meshing gears do not overlap, and a deliberately wrong spacing does. That is a geometry check, not a strength or life calculation.
  • The simulations are tools for learning and first estimates. Check anything that matters against a trusted method.
  • OpenPara is young software under active development. Expect rough edges, and please report them.
Screenshot: sketch with constraints
(coming soon)
Screenshot: assembly
(coming soon)