I don't think there would be anyway to do that w/out features as how you'll read the data??
You should use what is known 'Geometry Recognition' tools. The most famous for SolidWorks users I assume is FeatureWorks. You can use FeatureWorks API to recognize the feature tree and identify ribs. You can also use 3rd party libraries like Geometric's one: http://feature.geometricglobal.com/
Artem Taturevych, Application Engineer at Intercad (Australia)
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