Sculptris OBJ into UE4?

I haven't used Sculptris before. I imagine you can get it into Maya (or Maya LT) and then export as an FBX model with the smoothing and everything intact. With Maya, you can also retopologize the mesh so it will perform better in real-time. Hope that helps.

Any free software or demos that can export as FBX? I tried a search and didn't see anything.

Blender can export to .fbx, never used Unreal, so I can't guarantee it will work perfectly, but it's worth a shot. If you have access to it I would encourage taking the time to learn Zbrush, the zclassroom series of videos on the pixologic site is a great way to start. It's a lot like Sculptris, but much more varied in terms of brush options and it has great topology tools like Zremesher and Decimation master to simplify the process of turning a high-poly model into something with good edgeflow and a polygon count that will be usable in a game engine. It also has UV master for automating the UV-unwrapping process, it takes some tweaking to get UVs that are as good as the ones a skilled texturer could create manually, but for a quick and dirty texture map you can mess around with in photoshop, it generally does a decent job. Don't mind to come off as Zbrush PR, but outside of Blender, which I use for creating low-poly base meshes, Zbrush is the only tool I use for modeling and I think it's one of the best.

Thanks Twitchmonkey,
I have Zbrush and have jumped in to mess around a bit. Usually I can wrap my head around a program in a week or two, but the Zbrush UI is downright frustrating to even learn the basics. I'll try again to use the tuts but even those can be confusing when my software version doesn't match theirs.

I'll give Blender a shot and report back if an FBX file will cleanly import into UE4. Thanks again!

Test #1 SUCCESSFUL.
I was able to view my robot creation (I call him B.R.U.T.U.S.) in VR at 100% scale!
I imported my OBJ sculpt into Blender then exported as FBX. Import into Unreal and done.

Nice.