I've just started to use SketchUp, but I have a lot of experience in writing FEA code. One thought I had was to link SketchUp with FEMhub which is being developed with a web-based interface so it could be used in a web view via a plugin. They are working on 1D, 2D, and 3D solvers. Their web interface is a bit much for a plug-in, but it's probably a good place to start.