3D Printing

Game character models or like the warhammer type models are hardcore for some kinds of printers. If you're using a $300 clone printer you're going to want that dialed in really well before you even attempt printing.

Then, you have alot of designers who optimize their stances and such relative to the orientation they provide. So to try to optimize it better than them is a higher skill you learn from experience.

As a begineer, go with the orientation the designed made it; within reason obviously.

>and ensure a smooth finish on my FDM printer?

After your printer is tuned well. This is all about layer height.

I would note as well, most of these intricate character prints are usually done with an SLA or SLS printer. FDM really struggles at these.

Long story short: you have to adjust the model itself. Video game meshes aren't made for 3D printing and especially aren't optimized for FDM-style additive manufacturing. You have to apply the lessons you learned from mechanical 3D print prep; no freestanding objects, make sure everything connects to the base of the print. Even then, it's going to take time to get it right and you'll almost inevitably need supports if you're not using a resin vat printer.

It's a laborious process, sadly. For simpler character models (eg. Toad from Mario) it probably wouldn't be hard to fix up. If you intend to 3D print Vicar Emilia though, you've got a lot of work cut out for you.