I've used a wide variety of paint on Shapeways models.
https://www.shapeways.com/product/GPJ5HWKWG/cnsm-741-776-silverliner-series-coach?optionId=43359825&li=curatedproductGroup
This is one of 145 North Shore models I have in N Scale. I used Floquil, Testors, Mr. Surfacer and Krylon primers. The finish colors are either Tru Color, Floquil or Scalecoat. I also used various grades of sandpaper to smooth out the rough finish.
It is important to use a stripper like Bestine to remove wax residue. Sometimes I let them soak for a week or more although a few hours is usually enough. No paint will stick to the wax.
https://www.shapeways.com/product/49WZ95LTK/cnsm-741-751-series-coach?optionId=42483676
https://www.shapeways.com/product/SCJRWM3PN/cnsm-electroliner?optionId=42646899
The Electroliner is painted with "One Shot" sign painters paint. Once the sanding was all done, it left me with a wonderful glossy finish for decaling.
Randy Stahl
I don't have any hands on experience with Shapeways printed parts. Keith Kohlmann wrote an article in Kalmbach's 25 Freight Car Projects. He finished an FUD Shapeways N scale gondola. He used Bestline solvent and thinner to clean the body prior to painting. He also suggested Simple Green. There is no mention of the type of paint he airbrushed. I'm sure Shapeways could answer all your questions.
I have aquired many Shapeway interior pieces to model the interior of the Box Factory in Staples MN. They are very small. Do any of you have successful experiences painting these. Advice is requested on prep, holding, and painting, including what paint works the best. Thanks.