Group Mesh
To create a compound mesh from several independent meshes.
Usually, a mesh is a set of triangles with neighborhood relations. It is the reason why sometimes, when you create a 3D mesh or import an exploded mesh, several meshes can be created if the software does not find a path to link the different parts. In some cases, it can be useful to make a single mesh of several parts into a single entity:
To export a single file made of many parts: for example you could create a single STL file with a hollow sphere (no path between inside and outside surface).
To calculate a Best Fit Registration considering many parts as the reference immobile object.
To Inspect considering many parts.
A compound mesh is a set of individual meshes having no relation together. You can see the number of parts that are inside a mesh using the command Properties.
Select all the meshes you want to group and launch the command.
To recreate exploded parts from a compound mesh, you just need to select it and to use the command Ungroup Mesh.