getExtrusionLightnessFactor
Get the extrusion Lightness Factor (-1.0 = Dark, 0.0 no lighting added, 1.0 = light)
Return
the float value of the current lightness factor
Get the extrusion Lightness Factor (-1.0 = Dark, 0.0 no lighting added, 1.0 = light)
the float value of the current lightness factor