TECHNICAL NOTE: Group is equivalent to a simplified Transform node; it could be prototyped as:

     PROTO Group [
       eventIn MFNode addChildren
       eventIn MFNode removeChildren
       exposedField MFNode children  [ ]
       field SFVec3f bboxCenter 0 0 0
       field SFVec3f bboxSize  -1 -1 -1 ]
     {
       Transform {
         addChildren IS addChildren
         removeChildren IS removeChildren
         children IS children
         bboxCenter IS bboxCenter
         bboxSize IS bboxSize
       }
     }

Group is a standard node in the VRML specification because implementations can represent a Group more efficiently than the more general Transform, saving memory and slightly increasing rendering performance when the user wants only grouping and not transformation functionality.

The most difficult design decision for Group was what it should be named. VRML 1.0 also has a Group node, with similar but not identical functionality. It was feared that having a VRML 2.0 node with the same name but slightly different semantics might be confusing; the VRML 2.0 Group is semantically more like the VRML 1.0 Separator node. After a long debate, it was decided that naming decisions should not be influenced by the VRML 1.0 node names. It is expected that the number of people using VRML 2.0 will be much greater than the number of people who ever used VRML 1.0. Therefore, easy-to-learn and easy-to-understand names were chosen in favor of easing the transition from 1.0 to 2.0.

EXAMPLE (click to run): The following example illustrates use of the Group node. The first Group node contains two children and shows typical use of the root Group as a container for the entire scene. The second Group node contains three Shapes and is instanced later as the second child of the root Group node:

#VRML V2.0 utf8
Group {            # Root Group node
  children [
    DEF G1 Group { # Group containing box, sphere, & cone
      children [
        Transform {
          translation -3 0 0
          children Shape { geometry Box {} }
        }
        Transform {
          children Shape { geometry Sphere {} }
        }
        Transform {
          translation 3 0 0
          children Shape { geometry Cone {} }
        }
      ]
    }
    Transform {
      translation 0 -3 0
      children USE G1     # Instance of G1 group
    }
  ]
}