Since the test print of my coal wagon arrived a few days ago I've spent some time improving the 3D model in order to correct some of the outstanding issues with it. Unfortunately as I've added new features to the model I've run into a few problems.
Essentially the model is constructed in Blender by adding a large number of components together via a combination of boolean, array and mirror modifiers (they all do what you would expect given their names). One problem is that sometimes the boolean modifiers don't seem to do what you would expect (on occasions a union seems to have the effect you would expect from a difference modifier). I'm not sure what the problem is (it isn't inverted normals), but it means that I've had to move away from merging every part into a single object. This isn't a problem as Shapeways will accept files that contain multiple overlapping objects and print them as a single shape. Experience, however, shows that sometimes Shapeways gets confused, as an uploaded model will look completely wrong in the generated preview image.
The solution to "fix" such models seems to be netfabb Studio Basic. I'm not going to go into any details on how to use netfabb as there is already a good tutorial, instead I thought I'd show you one of the fun side effects; it can generate anaglyph images.
Once you have loaded your object file into netfabb, you simply right click on the object and from the Extras menu choose Stereographic View. The image above uses the standard red-cyan colouring. If you've read any of my other blogs (see here, here, here, and here) then you'll know I have an interest in 3D images/photos even if most of the people who read my blogs can't see them for one reason or another. Anyway, not only is it fun to play with this view in netfabb, but it actually gives you a much better sense of the object you are modelling than just viewing the 2D rendering in Blender; it's almost as if you are holding the item in your hand!