Скачать или смотреть Roblox Studio: Reduce Part Lag (Model to Mesh Conversion) | Mini Tutorial 6

This is a basic overview of how to reduce part counts on maps, models and other assets. This will reduce lag in Roblox studio and in the experience itself

Then this is what you need to do:
1) Group the parts of the same color (If you don’t, then you won’t be able to color them properly)
2) Export as an obj extension
3) Import to blender
4) Export to obj
5) Import to roblox

Blender download:
https://www.blender.org/download/

Information duplicated from video:
OBJ Files
•Geometry only: Stores just the 3D mesh (vertices, faces, UVs, normals).
•Materials: Can link to an external .mtl file for basic color/texture info, but Roblox ignores most of it.
•No animation: OBJ cannot store rigging, bones, or animations.
•Use case in Roblox: Good for simple static models (props, terrain pieces, architecture

How Unions Work in Roblox
•A UnionOperation is created when you use Union or Negate on parts in Studio.
•Roblox has to store the CSG (Constructive Solid Geometry) data for that union — basically, the math equations for all the cuts, subtractions, and merges.
•When the game runs, Roblox dynamically calculates/render these CSG shapes. That makes them heavier on performance, especially with lots of unions or complex shapes.
•Even “simple looking” unions can be complex under the hood, because the engine still keeps the original Boolean math structure.

How OBJ Meshes Work
•An OBJ mesh is just raw triangle data (vertices + faces).
•Roblox converts it into a MeshPart, which is stored and streamed efficiently.
•There’s no “math” to recalculate at runtime — the mesh is already baked into a static 3D object.
•That makes it lighter on memory and CPU, and generally less laggy than unions.