staticFrictionCoefficient 0.1 - 2 Static friction keeps you in the same place when you are stopped on a hill. This friction coefficient is usually higher than sliding friction.
slidingFrictionCoefficient 0.1 - 1.5 Sliding friction coefficient determines how much friction force occurs once the node has started sliding. The friction does not transition instantly from static to sliding friction, but gradually moves toward sliding friction as the sliding velocity increases. To control this effect, see "stribek velocity" below.
hydrodynamicFriction 0 - 1.5 This friction coefficient is used to add some extra friction as sliding velocity increases. This is useful for replicating fluid viscosity or speed sensitive friction effects of somewhat fluid-like ground types (soft dirt, sand, mud). If you decide that you'll simulate the fluid like behavior with the more complex fluid physics below, then just set this to 0.
stribeckVelocity N/A The stribeck velocity defines the shape of the static-sliding friction curve. A small stribeck velocity will cause an abrupt change from static to sliding friction, a large stribek velocity will make a slower transition that will feel more "sticky". The inverse (1 / stribeck velocity) is often described as "stribeck coefficient". Reference values can be found in either form, so make sure not to confuse them when looking up reference data.
strength 0 - 2 This parameter raises or diminishes surface friction in a generic way. It is here so as to be able to do quick calibrations of friction. Start with having this to 1.0 and after tuning the rest of the surface variables, come back and play with this.
defaultDepth N/A This parameter sets the depth of the surface fluid in meters.
fluidDensity N/A Density of the surface fluid (kg/m^3).
flowConsistencyIndex N/A Determines the speed sensitive drag effect. If <1 then fluid is Pseudoplastic (ketchup, whipped cream, paint) and has less drag coefficient at high speeds. If =1 then fluid is Newtonian, having equal drag coefficient at any speed. If >1 then fluid is Dilatant, having higher drag coefficient at high speeds.
dragAnisotropy N/A Upwards/Downwards drag anisotropy. This creates a lifting or sinking effect on the node when it slides through the surface fluid.
skidMarks N/A False = No skidmarks, True = Skidmarks.