Molecule structure STL files are generated by OpenSCAD, of which program is generated by "sdf2scad.perl" Perl script from NCBI PubChem database (3D SDF format files). About generating scripts and note, see http://www.thingiverse.com/thing:689652 (Water and Ethanol). Good health for your 3D printer!! Vitamin C (L-ascorbic acid, C6H8O6), Vitamin E (alpha-tocopherol, C29H50O2) and one of a kind of OPC (proanthocyanidin A2, C30H24O12). Construction 3D data (SDF file) is from the PubChem Project https://pubchem.ncbi.nlm.nih.gov/ .See http://www.thingiverse.com/thing:689652 (Water and Ethanol) for detail. I used Microsoft Model Repair Service (https://modelrepair.azurewebsites.net/ , need MS account) for generated STL using OpenSCAD. The Vitamin E and OPC are biggest within my chemical work series - some printers maybe difficult to build. With my Da Vinci 2.0 printer, model is scaled to x8, pitch 0.2mm, low speed and used single extruder (with white filament) worked the best, however, 4 hydrogen atoms dropped out. I cut off hydrogen from unused caffeine, bond with acetone (melts ABS) and fixed... chemically wrong sentence!! :-P