If you have been freelancing in 3D art for a while and just landed your first game client, the gap between delivering a polished model and getting it working inside Unity or Unreal can feel surprisingly wide. Polygon counts, naming conventions, texture channel assignments, pivot points - these are not things clients always brief you on, and figuring them out mid-project costs time you are usually not paid for.
Where things go well
On the upside, both Unity and Unreal have mature import pipelines. FBX remains the most reliable format, and engines like Unreal 5 now support Nanite, which means high-poly meshes from ZBrush or Blender can come in with far less manual retopology than was needed 4 years ago. If you are working with a client who has a technical artist on staff, handoff is usually clean - they handle the engine side, you deliver the asset to spec.
Where things get messy for freelancers
The problem is most small studios and indie clients do not have that person. So you end up troubleshooting LOD settings, material slot mismatches, and broken UV seams that only show up under the engine lighting. Unreal in particular has strong opinions about texture naming - roughness, metallic, and AO often need to be packed into a single RGB texture, and if your client does not tell you this upfront, you are reworking deliverables.
Pros
Engines handle a lot automatically now. Real-time previews let you catch errors fast. Demand for freelancers who can do both modelling and basic engine integration is growing, and that skill gap means you can charge more - typically NZD $85 to $130 per hour versus pure modelling rates.
Cons
Scope creep is constant. Integration work is rarely scoped in the original brief. Without a clear technical spec from the client, you will spend unpaid hours fixing import errors that were never your fault to begin with.