I have been browsing around for a few different items I will eventually need and I see some parts on sites like cults or cgtrader that are modeled but "not ready for 3d printing".
What is the process, or is it possible to make these parts "ready"?
I know a couple locally who can print but not sure if that will be the case with a file(s) that are noted as above.
What does this really mean?
If the file format is STL, 3MF, or OBJ, it can be opened in a slicer and prepared for 3D printing. Pre-sliced models sound wonderful, provided all your printers and filaments match those used to prepare the pre-sliced model.
For resin printing, you may see the term pre-supported, which merely means the supports are in place. The quality of the support placement can vary. Depending on printer and resin the supports may be anywhere from superb to not so great. You may need to add or move supports. Note that pre-supported models are not in a different format, the files you use with Lichee or Chitubox slicers for resin printers are again the usual STL, OBJ, and 3MF file formats. A model may be both pre supported and printer ready, avoiding the need to use a slicer, although reading the fine print may be a good idea, as what prints well on a recent higher end resin printer using ABS like high speed 8K+ resin may fail completely on a five year old printer using generic basic resin.
In some cases the formats of the available files are for use with some form of 3D modeling, VR, or 3D CAD program, which many slicers do not handle at all. STEP is a common format for making 3D models available in the CAD world. Commonly used 3D CAD programs would include Solidworks, Alibre, Fusion360, and perhaps FreeCad. FBX, and ".blend" file extensions are typical for the Blender 3D modeling application. zBrush amd Maya have their own file extensions. Most people looking to share or sell files tend to make the files available in either a variety of formats or at least in a format used by more than one package.
CGTrader particularly has many models for use in CAD, modeling, and architectural applications that can't be fed into a slicer and in many cases are not designed for 3D printing as there is no expectation of using them for anything other than display or to supplement or incorporate into a virtual model. These models may be anywhere from simple to insane to get into a form that can be 3D printed. What is needed may range from just a bit of slicer magic to using several different packages to dissect the model into components that can perhaps then be printed.
There are ways to import most 3D file formats into something like blender, then export the file as an STL. This requires a few free add ons, and the generated model may not be manifold (AKA watertight). Manifold is a fancy way of saying if the slicer can't figure out whats "inside" and what's "outside" it has a hard time knowing what to do. Insert favorite topology joke here. In some cases slicers such as OrcaSlicer can repair these issues, but you have to be running on a Windows platform as they use some Microsoft specific stuff. Not great if you're a linux person...
Lastly but worth keeping in mind: There are 3D printing technologies out there that can handle models that are not printable using home level printers. These models may be quite economical to get printed by a service outfit like PCBway or others, typically using powder bed fusion technology.
That's about as simple as I can make it without over simplifying I think, it can be a real can of worms.
