I am a science teacher working on printing molecules imported using the Molecule Importer plug-in. I can print them, but it would be easier and less of a workflow with a cleaner STL export. The issue is that the bonds extend into the spheres that represent the atoms, and that makes for a messy print. So the goal would be to import the molecule and use Sketchup tools/plugins to make it into a clean STL export that slicer software (I’m using Cura) will cleanly print. Thanks in advance for the help!
If you make each of your atoms and bonds a solid component, you don’t need to merge them into a single solid for 3D printing. In your model, the bonds are open-ended cylinders and need to be closed to become a solid. In the attached model, I created each atom and bond as a separate component and simply positioned them where I wanted them to be. Most slicers can handle the individual components, although some may not deal well with nested layers. The STL export from the attached model was imported into Slic3r: