The thing is that you don't need to settle for 80% and you don't need to reinvent the wheel - you can have 100% for free by installing Salome-Meca as a companion program, and controlling it including regeneration of meshing and loads from FreeCAD using Python. The main app could (and probably should) therefore reside in FreeCAD which would generate drawings, idealsation etc, and possibly reports for standard analysis cases that are supported. Although Salome-Meca runs only on Linux, Windows users can also access Code-Aster (analysis engine in Salome-Meca) running on a server http://www.alneos.com/en/download/codea ... -the-cloud
, and there are some Salome Windows binaries http://www.salome-platform.org/download ... nt-version
For example, you could create a bridge deck design application for prestressed concrete bridge decks with insitu reinforced concrete deck slab, where you create a schematic arrangement of setting out of the prestressed beams, and support abutment bearings, with the standard precast beam etc. designation entered, and choose to have your app generate either a grillage or a FEM model and loadings, and create an analysis model in Salome-Meca. You would then refine the analysis and complete it in Salome-Meca, use a third party commercial prestressed concrete design package, and once the section sizes selected have been proven, have FreeCAD generate drawings including sections and details some of which are automatically generated, and some of which are manually added.
The reason for using Salome-Meca as a companion package to which FreeCAD is a front end rather than trying to do too much in FreeCAD itself is for maintainability reasons. Salome-Meca is an extremely powerful, comprehensive and professionally maintained FEM, stress visualisation, reporting and analysis engine. It has meshing tools, supports various import/export formats, has various visualisation and reporting tools, and even an equivalent of make (YACS) for managing changes and dependencies in input files. In real life, it is also necessary to use other commercial design and analysis packages for specialist applications. There are a lot of very good FEM, analysis and design packages out there (the majority of which are commercial) and Salome-Meca is one of them. If you try to do too much in FreeCAD by re-inventing what is already out there, then you will end up with something second rate, with limited functionality, and something which will be unmaintainable because there is insufficient resourcing for maintenance.
The big potential I see in FreeCAD for FEM and analysis is format compatibility and cross application python scripting with Salome-Meca and other packages, and the fact that it can be used to automatically generate both drawings, and analysis models/data, and also other output like bills of materials, weights etc. While the market is crowded with very good modelling, analysis and design packages, what is lacking currently in the process is the automation of drawing production, and production of bills of materials and their integration with the design process. It is really strange and nonsensical that while we have sophisticated 3D analysis and simulation and a high degree of automation, we still produce drawings by manually drawing out lines using a line drawing CAD package like AutoCAD, and manually add up and measure quantities for bills of materials that go into contract documents, when these things are the things that are the most tedious and repetitive operations and should be automated first. This is the real bottleneck in the design process nowadays, rather than analysis or design, particularly in the civil, structural and architectural fields where the structures, drawings representing them, and contract documents created to construct them are very complex and voluminous.
I see the big potential for FreeCAD in CAD drawing and BoM automation, and as a container for specific integrated design applications which leverage this automation by leveraging where necessary other packages like AutoCAD or DraftSight for finishing drawings, Salome-Meca for analysis and exporting into other analysis formats, and custom python scripted output for import into other commercial packages. The problem with CAD and design in open source development is that it requires a high degree of specialisation in a particular field, which means the time and resources that contributors can devote to development is very limited. In this context, it is important to leverage existing applications (open source, and commercial) where necessary, and to focus effort where it is really necessary.