This example displays a scene containing a set of NumXxNumYxNumZ SoBufferedShape
representing a CAD standard part containing about 34000 triangles and loaded
from an external .iv file: screw_buffered_shape.iv. A GUI is set up with three
sliders connected to the number of instances created along the X, the Y and Z 
world axes. The instances are disposed with a regular geometrical pattern
in space, inside a cube, with scale factors applied and rotations applied in a cycle.
