Hi, I used a previous version of the Units library to sketch out a fps system (foot-pound-second) that paralleled the cgs system, and the code compiled and ran fine. I am now returning to this effort, and I want to wrap it into a coordinate transform package, but I can no longer get the code to compile. I am using the latest code from the Boost sandbox, and MS Visual Studio with WinXP. The problem appears to be in the conversions, but I don't see what is missing when compared to cgs. typedef unit my_unit; typedef quantity< my_unit, ofs::Real64 > linear_measure; linear_measure dummy(200.0*CGS::centimeter); // implicit conversion from SI::meter to CGS::centimeter linear_measure dummy2(200.0*FPS::foot); The first three lines work fine, but the last one generates 10 errors with my compiler (MSVC 8.0). The first error is boost/units/detail/conversion_impl.hpp(342) : error C2039: 'type' : is not a member of 'boost::units::detail::call_base_unit_converter' with [ Source=boost::units::foot_base_unit, Dest=boost::units::unit>,boost::units::dimensionless_type>,boost::units::length_dimension>>> ] boost/units/detail/conversion_impl.hpp(536) : see reference to class template instantiation 'boost::units::detail::conversion_impl<N>::apply' being compiled with [ N=1, Begin=boost::units::dimension_list>,boost::units::dimensionless_type>, DestinationSystem=boost::units::homogeneous_systemboost::units::meter_base_unit,boost::units::dimensionless_type> ] boost/units/detail/conversion_impl.hpp(216) : see reference to class template instantiation 'boost::units::detail::conversion_factor_helper' being compiled with [ Source=boost::units::unit>,boost::units::dimensionless_type>,boost::units::length_dimension>>>, Dest=boost::units::unit>,boost::units::dimensionless_type>,boost::units::length_dimension>>> ] boost/units/detail/conversion_impl.hpp(324) : see reference to class template instantiation 'boost::units::detail::call_base_unit_converter_base_unit_impl::apply' being compiled with [ Source=boost::units::foot_base_unit, Dest=boost::units::meter_base_unit ] boost/units/detail/conversion_impl.hpp(342) : see reference to class template instantiation 'boost::units::detail::call_base_unit_converter' being compiled with [ Source=boost::units::foot_base_unit, Dest=boost::units::unit>,boost::units::dimensionless_type>,boost::units::length_dimension>>> ] boost/units/detail/conversion_impl.hpp(377) : see reference to class template instantiation 'boost::units::detail::conversion_impl<N>::apply' being compiled with [ N=1, Begin=boost::units::dimension_list>,boost::units::dimensionless_type>, DestinationSystem=boost::units::homogeneous_system>>,boost::units::dimension_listboost::units::steradian_base_unit,boost::units::dimensionless_type>>>>>>>>> ] boost/units/detail/conversion_impl.hpp(372) : while compiling class template member function 'boost::units::quantity boost::units::conversion_helper::convert(const boost::units::quantity,Y> &)' with [ Unit=my_unit, Y=ofs::Real64, From=boost::units::quantityboost::units::length_dimension,boost::units::FPS::system,double>, To=boost::units::quantity, Dim=boost::units::length_dimension, System=boost::units::FPS::system ] boost/units/quantity.hpp(167) : see reference to class template instantiation 'boost::units::conversion_helper' being compiled with [ From=boost::units::quantityboost::units::length_dimension,boost::units::FPS::system,double>, To=boost::units::quantity ] testQuantifiedVector.cpp(47) : see reference to function template instantiation 'boost::units::quantity::quantity,double>(const boost::units::quantity,Y> &,void *)' being compiled with [ Unit=my_unit, Y=ofs::Real64, Dim=boost::units::length_dimension, System=boost::units::FPS::system ] Any guidance in this would be greatly appreciated. Pat