OpenSCAD is very picky about the STL files it wants to import and render. Try running the STL through netfabb studio basic (free), select repair - actions - remove degenerate faces - ok - apply repair - yes. It seems to work most of the time, if not you can play around with the other repair options, or resort to clean up the model in a mesh modeller like
Wings 3D.
Of course the "proper" way (as in, what I would do) if you want to use OpenSCAD, would be to make a DXF of the text you want, and use
linear_extrude to make it 3D. I wrote up a small
tutorial on how to use
inkscape to achieve this.
--
-Nudel
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