Floor in the Walkways

Tiles covering the floor on both  sides of the atrium; this is plastic material covered with a glossy varnish, it has some regular wavy bumps.
 

The 2D and 3D graphs below show the BRDF values as a function of outgoing angle Beta which is measured in respect of the surface normal. Note that the BRDF values are shown in logarithmic scale to suppress the size of specular lobes. Four graphs for different incident angles  0, 30, 60, and 90 degrees are presented from left to right. In the 2D graphs, various colors are used to mark different orientations of two planes defined by directions of  (1) the outgoing lighting and surface normal,  and (2) the incident lighting and surface normal. The color assignment is as follows: red - 0 degrees (the incoming and outgoing light is considered within the same plane), green - 45, blue - 90, and yellow - 135 degrees.

BRDF measured data. Complete reference for the file format given here.