This function returns the smoothness of a line or surface. In case the smoothness can be defined the degree will get assigned either
    0 - continuous curve / surface (i.e. degree 9)
    1 - the direction of the curve / surface is gradually changing (i.e. degree 1)
    2 - the change of direction of the curve / surface is gradually changing (i.e. degree 2)
In return value of this function retuns the dimension of the found smoothness:
    0 - smoothness could not be defined
    1 - found the smoothness of a curve
    2 - found the smoothness of a surface


public const string enginedll = @"engine.dll";

[DllImport(enginedll, EntryPoint = "GetSmoothness")]
public static extern Int64 GetSmoothness(Int64 owlInstance, out Int64 degree);    

Property owlInstance

Size: 64 bit / 8 byte (value)
The handle to the specific instance in the design tree. The instance handle is static within one open model but is most probably different when the same instance is opened in another model. The instance is always exactly of one unique class.

Property degree

Size: 32 bit / 4 byte (reference)
The degree of smoothness, a disconnected edge, or surface will return 0, a connected edge / surface will return 1, if the direction change of an edge / surface is connected it will return 2, etc.. The degree only returns relevant information if the sources are compiled to add this information (SMOOTHNESS).