Places like Thingiverse, Youmagine, etc. are great for downloading free models to print. However, people uploading these models are not necessarily aware what design considerations need to be done for a certain printer type to be able to print the model in question. Sometimes all your 3D printing troubleshooting efforts can be mute if the file just isn’t printable.

Some models are designed for resin based printers and will fail miserably on FDM filament based printers. There are certain geometries that are impossible to print with filament based printers and throwing supports at it might not be enough to make it work. There are STL files that are not meant to be printed at all. Some models that should print ok are plain and simple broken. Some print fine unless you try to scale them.

Downloading STL files is a hit and miss kind of thing. Some work, others won’t. You can try some of the free STL fixing tools, like Netfabb-online, MakePrintable.com or the like, but your results may vary. Not all STL files will print. Luckily MyMiniFactory boast guaranteed printable files, so this is usually a good place to start.

Something that might help you sort out the good from the bad when browsing these ‘free’ model download sites.

Taking Thingiverse as an example, if you see an object you are interested in printing, if there are no associated photographs of the printed object supplied by the uploader, and all you see is the system-generated blue object image – it might not be at all printable. Take a look at the associated comments section to confirm this one way or another.

It may be that the model is just fine, or has only just been uploaded. In any case, if there is another similar object that has photos, comments and lots of downloads, you might be better off looking to see if that meets your needs first.