Draw Harness

Draw Harness is an open-source Tcl command interpreter used to test and demonstrate Open CASCADE Technology (OCCT) modeling libraries.

It is an integral part of framework itself - see DRAWEXE executable withing OCCT installation path.

Unlike typical wrappers mapping OCCT C++ API directly to the other language, Draw Harness provides a set of manually written Tcl commands utilizing OCCT functionality, providing a more natural environment for interactive input, and even giving developers hints on how C++ API can be used in their application.

Draw Harness allows:

  • Performing modeling operations from OCCT.
  • Performing import/export operations into STEP/IGES/glTF/STL file formats.
  • Displaying and interacting with models in 3D Viewer, as well as making screenshots.
  • Learning, evaluating, prototyping algorithms interactively - though command line input or available Tcl samples.
  • Scripting operations using Tcl language for re-use in interactive and non-interactive modes.
  • Automated non-regression testing of algorithms.
  • Extending with own commands through writing Draw Plugins.

Draw Harness can be used on a wide range of platforms, including Windows, macOS, Linux, and even directly in the browser as WebAssembly module!

See also the Draw Harness User Guide.

application, SDK
Industrial sector: 
Mechanical engineering, Automotive, Industrial equipment, Shipbuilding, Aircraft, Architecture, Engineering, Construction
Software type: 
Open Source
Scope of application: 
3D modeling, Data Exchange, 3D viewer, Language Bindings, Web, CLI
Suitable for: 
Freelance, Enterprises, Personal, Startups, SMEs, Research & Science
Deployment options: 
Desktop: Mac; Windows; Linux
Web: Web-based
Support Options: 
Paid professional support, Forum/Community
Training Options: 
Open Cascade