On this page, I will describe the progress I make on the NLnet Lens/FreeCAD integration project. In this post on the enhancement proposal for variant parts. Important links:

• The FEP-0010: Variant Parts enhancement proposal
• Pull Request for Variant Parts enhancement proposal
• Official discussion on the enhancement proposal
• Announcement of the proposal on the FreeCAD forum
• Agenda item for the Developer Meeting on 5 October 2025 (point 5)
• Meeting minutes for the Developer Meeting on 5 October 2025

One of the first tasks is creating an enhancement proposal for Variant Parts. An enhancement proposal is a formal process to introduce large new changes to FreeCAD. Since the discussion may take a while, I focused on this part first.

Variant Parts are not only useful for parametric modeling, they are also useful for the Lens platform. The variant parts give users what I call an "Application Geometry Interface" in the form of properties that users can change to parameterize a part. This Application Geometry Interface serves two purposes: It makes it possible to create a variant by changing one of these properties. It also make it possible for the Lens platform to provide users these properties on the website to parameterize the parts.

With the Variant Parts enhancement proposal, the FreeCAD community can be involved before the code has been written for a change as large as this one. Since this proposal has already been preceded by the Research Variant Parts project (outcomes here), I have been able to move this proposal from the "Draft" staged to "Proposed" stage. We will now have a period of discussions before which this proposal will hopefully move to the "Accepted" stage.