Importing CAD models into Blender. SolidWorks -> Rhino -> FBX -> Blender. Works fine for rendering in Cycles.
But on export to .html, I get invisible patches in the model, due to the normals being flipped in that location.
Flip normals doesn't work. Make normals consistent doesn't work.
Even Shift+G (select similar normal) and then flip those ones doesn't work.
Seems to be watertight. How can we just make it point the normals away from the interior of the object?
Updated Blend File Here:

(source: giantcowfilms.com)


I could just import a fresh FBX, except not really because my real models may have 10x this many parts, and will all be textured, and re-import would mean too much lost work. Would prefer if I can to find way to fix the normals if/when this happens. Sometimes have to alter the model slightly in Blender, maybe that's what ruined them. Thanks
– sliver Sep 07 '16 at 23:34