I realise the title is a bit vague, but I’m wondering what the best method is for creating a gameplay space that whilst not huge in itself, is surrounded by a much larger environment.
For example, if you were to make a 3d tabletop game (think Warhammer, that sort of thing) which is always viewed close to the character (think any third person game), but you also wanted the real world room in which the tabletop game is being played in to be visible. I guess similar to the many UT maps of old where people are tiny and the world is someones bedroom, that sort of thing.
Obviously the scale needed for this outside world, even if you don’t venture into it will need to be very large, and as a result you might have problem lighting it. I know some games have given this sense of scale before using portals (for want of a better word), where the room is actually small and rendered elsewhere in the gameworld, but uses a camera to effectively create a 3d cubemap for the actual play space.
You would also want to set things like a Lightmass Importance Volume around the actual play space; that way Lightmass just does a single bounce pass against the distant geometry since you’ll never need much detail.
My approach would he to model the outer environment at “normal” size (so it has a detail level appropriate to being comparatively tiny when up close), and then just scale the entire thing way up (it will be too low-detail for any kind of close player interaction but at such a large distance should be fine).
Low vertex count + low lightmass bounces = should be decently light on performance
Check out the documentation on Lightmass Settings, you can see an example map from Epic set up in much the same way (very low-vertex large geometry in the distance, with a lightmass importance volume bounding the actual play space)