The XmlTkBackWallThicknessFrt structure specifies the thickness of the back wall of a chart as a percentage of the depth of the 3-D plot area. The back wall is the wall that is parallel to the category (2) axis. This structure MUST only be present if the back wall thickness is greater than 0. MUST only be specified if the chart contains a Chart2.4.46d record.
wallThickness (8 bytes): An XmlTkDWord that specifies the thickness of the back wall of the chart as a percentage of the depth of the 3-D plot area. The wallThickness.dValue MUST be greater than 0, and less than or equal to 100. The wallThickness.xtHeader.xmlTkTag field MUST be equal to 0x0035.