Agreed trusses need engineering, for that I am working on this project:
However, most designers just need the basic geometry, the actual engineering will come later. Also most designers/architects should have a basic enough understanding that for example a 2/2 King Post truss can’t span a 40’ clear span.
I’ve just setup a page for this plugin here for those wanting to test it out. The trial version is not limited in any way at the moment. I have a similar thread on Sketchucation but I thought it might be good to post here as well for more input and feedback.
At some point I would like to integrate the plugin with the engineering on my website but I’m still figuring out the SketchUp API, it does seem pretty full featured.