Is there a good way of splitting a model part in SolidWorks, in order to make each piece fit a SLS 3D printer ? After printing I could glue-up all pieces to one big part again. Can a part be split along some inserted planes ? My part is like a thin-walled shell.
I don't know Solidworks, but in my software, I can draw a line, then split my model along that line. You may be able to email service about this, and they may be able to help you out.
Try copying the original part then doing an extruded cut that eliminates the entire bottom half on one copy and do the same thing eliminating the top half of the other copy. Add some alignment tabs to the pieces so they will fit back together securely and in perfect alignment. Next you'll need to place both of the pieces into a new assembly and add some sprues between them to create one easy to handle part for 3D printing. Save the finished Assembly as a Part, use the Combine command to join all the solids in the part as one piece and save the result as an STL to upload at Shapeways.
If you want to get more technical with it you can do what the above says about extrude cutting, but make a configuration for the part for each. That way if you make any changes you don't have to change both separate files.