BCGControlBar Pro for MFC
CBCGPBrush BCGPChartFormatArea::m_brFloorFillColorSide3D

Used to fill the left or right face of thick floor in 3D charts.

You can set this brush to customize appearance of thick floor in 3D charts. This color can be generated automatically from m_brBottomFillColor with Generate3DColorsForThickWalls().