I thought it might be instructive to explain the design – why it was done the way it was. (Click the images for a larger version)
First of all, the dimensions shown are in mm.
2.750 : Looking at several spray cans … Krylon and Ruatoleum, the can measures 2-19/32″ diameter – or – 2.594″. Divide that by 24 and we get 0.108″ – or – 2.75mm
1.950 : Note the 0.100 width of the lip. This .1 mm is the minimum embossed detail possible when printing in a Frosted Detail Plastic at Shapeways. This means the model will have that slight raised ridge or lip around the top and bottom of the can. Looking at a spray can this lip actually is pretty much level with the can diameter – the can actually ‘necks in’ just above the lip. I may do a Ver 2 of the can that way with a .1 x .1 groove to create that lip. This will do for now though.
6.625 : simply the height of the can .. nothing to see here.
0.100 : Top of can for the grooves. That again is the minimum ‘engraved’ detail possible
0.0300 : Very top of can – this is the minimum wall possible when printing in a Frosted Detail Plastic
0.042 : Most likely that will simply be ignored by the printer. It depends really on the position of the print head relative to the mesh at the time.
0.350 : Wall thickness. I have found that trying to ‘hit’ the magic minimum wall thickness of .3 mm is very problematical when dealing with a curved surface. Simply bumping up the number a bit saves lots of problems
0.400 : This is the size needed (minimum) for an escape hole – to allow the support material to drain. Honestly this could be made larger but that would mean a larger hole to fill if the modeler had the can laying on it’s side. No big deal really .. even .8mm dia hole would only be 0.030″ dia and easy enough to plug.