IUnk Query(string typeName)
The method gives access to other interfaces of an object. See samples and your development system documentation for more details
Example:
void f(IAppearance_DG appearance) { IMaterial_DG material = appearance.Query("IMaterial_DG") as IMaterial_DG; //Or IMaterial_DG material2 = appearance.Query<IMaterial_DG>(); //Or IMaterial_DG material3 = appearance.As<IMaterial_DG>(); }