Free and Open Source OCC based CAD software

Hi all,

I just got the news about the first public release of NaroCAD. I'm although a bit confused with the different CAD projects currently in development. I've bookmarked 4 projects that both use the OpenCASCADE library:

Total Engineer:

I download and test each new release of these projects, and I must say that both of them *seem* similar (all my apologies for the different dev teams, it's just my feeling): basic features, OCAF based, 3D viewer, part design, sketcher, scripting engine etc.

I then have a few questions:
- did I forget a project?
- what are the differences between these projects (there must be, but I didn't get them)? In other words, in what way do they differentiate from each other and from available commercial and proprietary products?

Best Regards,


jelle's picture

python based / related:


C# based:

-Total Engineer

This could be a very interesting thread: surely all these projects share a lot of workload, so it would be *really* constructive if at least the insights while developing these softwares can be shared. In this case kudos to the NaroCAD developers and also to HeeksCAD. These are great resources.

Roman's blog is a small renaissance in the exchange of OCC related knowledge to. Perhaps this raises the question whether it would be interesting to see if its possible to find a model such that the sum of all OCC' related blogs is greater than its parts? Perhaps a document on SVN ( latex or alike ) such that OCC documentation would get a serious boost?



Pawel's picture

Hi Thomas, hi all,

there have already been a couple lists with OCC-related projects compiled:, Roman's blog also has a corresponding section. So I guess, there are actually quite a lot of projects out there using OCC.

Regarding Total Engineer, besides the scripting engine:
- it is capable of detecting collisions and can compute distance between two/multiple objects - these functionalities can be used to create CAM applications. I'm planning to release a sample CNC PlugIn to demonstrate those (and maybe even more!) functionalities but at the moment I can't specify any date...
- based on Roman's blog I created a TopologyExplorer which I think is quite helpful if one wants to understand the OCC geometry model.

In comparison to commercial systems it is usually much faster (cheaper) to create a specialized, customer-oriented application (within the CAD/CAM/CNC domain) with Total Engineer than with other products...

Hope it clarifies a bit.