They wouldn ' t be sitting at my table if they didn ' t . <| sep |> The most important thing for a large play space is using an LOD system . You can decide about whether or not to instance your dungeons later maybe even on a casebycase basis but to start , LOD should an immediate priority or your prototype will almost immediately become unplayably slow . Draw large terrains in square chunks , so you can render them at lowerdetail when you ' re farther away . Then , apply this concept to the props inside the terrain chunks , too . Smaller props can disappear entirely when they ' re far away . GTA V takes this to the extreme an entire city block , including buildings and such , can be reduced to one superlowdetail mesh when it ' s beyond some maximum distance . If I had to guess , I ' d say they probably generate the lowdetail terrain texture automatically from the highdetail version of the area , including all the props and streets and buildings , then somebody goes through and manually adds in some extra shapes for the importantlarge 3 D buildings . Image taken from this awesome b r eakdownvgraphicsstudypart 2