You probably know Nerf Guns, every part is plastic (except for springs, motors... duh). I've decided that I want to modify a Nerf blaster I bought to be more powerful. Currently it fires about 20-30 feet... if you're lucky and if you're waiting for the motors to all the way back up (it uses a "flywheel" system to semi-automatically fire darts). Honestly, I never really bothered to look much at Shapeways until I got done with the parts, so I guess this is more or less an explanation of what I've done thus far. I've taken my gun blaster apart and have stripped out the motor and wheel assembly pictured here (minus the wheels, I seem to have lost one..) Motor mount as assembled in the blaster What I plan on doing with Shapeways is to print a new version of the mount for the motors so that it accepts some larger motors I've purchased. Additionally, I plan on having a pair of new wheels printed for this because I had to change the spacing of the motors so that they would fit, not to mention the original wheels were too small to fit around the motor like the original placement. Motor mount and wheel with new motor (left) and original motor (right). Size of new motor compared to original motors in assembly So far I've modeled the original mount (to make an accurate replacement) in Autodesk Inventor (the software I use for school) and used that to make the replacement. It's taken me a few weeks of on and off hobby work on it, but I have it finished. Motor mount models side-by-side After making that and easily making models of the motors, I used the replacement mount to then produce a set of wheels that would work in the assembly the same way the old wheels would, and from there I have my final assembly model. Motors are in blue. Mount is in white. Wheels are in orange. Dart (being launched) is in cyan. I am hoping to send the order in soon to get these (three) parts made, but converting the models seems to be giving me quite a bit of trouble, whenever I upload it, the dimensions turn out to be something absurd like a volume of 90.83cm^3 for one of the wheels when in Inventor I get a more moderate (and correct) volume of .338 in^3 (5.539 cm^3). I've tried uploading in multiple formats like .stl, .wrl, and .dae (via the recommended converter) and still none of them gives me the dimensions which I used in the design of each model. So at this point I guess I'm stuck and would really appreciate any help at all.