So yes, I have used the search feature and read previous answers (let me clear myself first) but I still have questions.
I’m working a game and found the perfect asset bundle on Unity/Sketchfab (literally everything I need), however it is not set up for Unreal. The artist said that importing the .fpx and setting the materials correctly would be an insane amount of work (its like 400 assets). How would one theoretically do this process and how time consuming would it be? Are we talking 10 hours, a few days, weeks, months?
Do you mean .fbx or .fpx? Anyway, it really depends how much work you have to do to edit the materials. The two factors that are going cost time is the load process and material adjustment. With a huge 400+ asset pack, time just to bring it into Unreal could take an hour. Unreal generates basic materials automatically. It works well for simple things that just work by plugging into a texture coordinate, but I’m not sure how well it handles complicated materials. If the assets have a really complicated Material, you might be stuck adjusting it yourself. Feasible for basic adjustments like making something transparent as needed. Realistically, it could probably take a day’s work to bring in everything. Only would be more than a day if you had serious problems. For instance, Unreal only lets you import skeletal meshes with one root bone. Any skeletal meshes with more than one root bone would have to be adjusted in other 3D software like blender.