Second Life uses a prim (or primitive) creation tool that you can easily manipulate. Creating multiples of these you can make anything imaginable. The only problem is there is a limited amount you can use as these prims affect Land Impact (the amount of prims allowed within each loaded section). Originally this meant you couldn’t make very much without either having tons of prims for detailed items or very few prims but detailed textures.
This changed when Second Life added the option to load Mesh dae files. The people who created Mesh Studio found out they could create a tool that could pull all of the linked prims ( joining them together to form one item much like Maya’s Connect feature) and create a mesh file without having to go through a 3D art program like Blender or Maya.
It is a decent program but is still limited by Second Life’s creation tool, which doesn’t have the rich features that 3D software like Maya or Blender have.