I attached the assembly file and the .STL file that I have been trying to print I used Autodesk Inventor Professional to create two rubics cube pieces in metric then I tiled the appropriate amount into a assembly file, I then saved the assembly file as a .STL so that i could upload it to Shapeways. but when i upload it and it asks what scale i am using, when i tell it millimeters it is a total of .8 cm wide (It should be about 8 cm wide) using inches or meters only makes matters worst. Any help would be much appreciated, thanks
Open the STL file in Netfabb Basic. (can be downloaded for free from www.netfabb.com) Click on Partt/Scale, enter the number 10 then click on the Scale button. Then, right click the model and select Export.. save it back as an STL You should be able to upload that version without trouble. Just a side note: many of your cubes are 2.2 mm thick, but some of them have walls that are either 1.7mm or 3.4mm - I think that top back row needs some attention.
Some time ago somebody here in the forums mentioned that Inventor uses centimeters as the export unit by default - this can be changed in an export options dialog.
This is true. Autodesk decided to use Centimeters as the units in STL exports as the default. Once you change it over to mm, it will stay that way until you change it again.