Making shapes hollow/Texture resolution

I have a WRL file with vertices and faces specifying the shell of the mesh. I assume Shapeways will treat it as a solid when I upload it, but is there a way to request it is printed hollow to save material and make it lighter? I know some printers allow you to use a honeycomb type structure on the inside to keep structural integrity while significantly reducing the amount of material that's used. I saw in another post there was a tutorial on how to make the inside a honeycomb but the link was broken..
I was also wondering what the resolution of the color material is - if I overlay a texture on my model, what lateral resolution will the texture be printed in?
Thanks!

You would have to import it in some appropriate design software and extrude the faces so that they become walls of at least 2-3mm thickness (or simply create a smaller copy of your model, stick that inside the original and close the seams). Honeycomb structure inside is not strictly necessary as loose material will act as support during printing. Texture resolution and color gamut is rather poor - think early 1990s inkjet printing on non-glossy paper - but I have never seen official figures for practical resolution (think it is marketed as 600dpi based on mechanical positioning accuracy and nozzle size, but the actual figure for textures is probably closer to 100dpi, good enough for most figurines or technical models, insufficient for aerial maps)