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 and Live Demo.

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, Scripting
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