RFI(plyFile)Relief index is calculated by the ratio of three-dimensional surface area to two dimensional area on meshes that represent specimen surfaces and have already been pre-smoothed in a 3D data editing program. Alignment of the point cloud will have a large effect on patch orientation and must be done in a 3D data editing program or {auto3dgm} prior to creating and reading in the ply file. The mesh must be oriented such that the occlusal plane is parallel to the X- and Y-axes and perpendicular to the Z-axis.