UltraSmartSaveInstance

A modified build of UniversalSynSaveInstance (USSI) that correctly saves UnionOperations (CSG MeshData2 geometry) and Terrain.

Usage

local synsaveinstance = loadstring(game:HttpGet("https://raw.githubusercontent.com/RiseBlox/UltraSmartSaveInstance/main/saveinstance.luau", true), "saveinstance")()
local Options = {} -- Full option list @ https://luau.github.io/UniversalSynSaveInstance/api/SynSaveInstance
synsaveinstance(Options)

What's different from the normal save instance

• Unions render correctly. Re-enabled gethiddenproperty during the save (it was being disabled unconditionally) so the union's MeshData2 is actually read, and stopped IgnoreSharedStrings from dropping the MeshData2 / ChildData2 SharedStrings. On executors that can't read union mesh data, unions fall back to a visible bounding-box Part instead of being invisible.
• Terrain SmoothGrid / PhysicsGrid are serialized.
• Faster, lighter saves — the file is assembled with a table buffer instead of repeated string concatenation, fixing the O(n²) growth that caused "not enough memory" on large games.

Note

ChildData is NotReplicated, so client-side saves render unions but can't make them editable/separable in Studio.

Credits

• luau/UniversalSynSaveInstance
• RealSlimShady2000/SaveInstanceMODIFIEDFullUnionSupport
• Claude