Regarding the VTI model in ANVEL, I have found a set of parameters under the menu VTI models --> Surfaces --> Sand (Dry), this field is called "SinkagePressureModel". Among other options, the user can select: MSG2010, MGS2013, DilativeMGS2014, Bekker, Bernstein Goriatchkin, and Upadhyaya; what is the meaning of this parameter? What are the differences between those models? Can we generate something similar? Following the same topic, what is the meaning of the variables: "SinkagePressureModelParam1", "Param2", etc. What is meaning of the variables: TrackMode (None, Always, ProlongedSlip), TrackValue, SurfaceFlags (None, Deformable, Dilative, SurfaceOnly, AlwaysAffectsSurface)? Thanks!