Definition from IAI: The IfcSpecularRoughness defines the
datatype for the reflection resulting from the roughness of a surface through
the height of surface impurities where the specular highlight is made sharper
with small values for the roughness, such as 0.1.
Applies to "glass", "metal", "mirror" and "plastic" reflection models.
Larger values, close to 1.0 decrease the specular fall-off.
IfcSpecularRoughness is of type REAL. It is constraint to values
between (and including) 0 and 1.
NOTE: The datatype relates to
the definition of "shiness" in VRML97, which is the reciprocate value to the
specular roughness.
HISTORY: New type in Release IFC2x
2nd Edition.
