/*BBTK_OUTPUT(TransferFunctionView,GreyLevel,"Greylevel related to the transparency",std::vector<double>,"");
BBTK_OUTPUT(TransferFunctionView,Value,"Value of the transparency in the transfer function",std::vector<double>,"");
BBTK_OUTPUT(TransferFunctionView,GreyLevelColors,"Grey level of the color in the transfer function",std::vector<double>,"");
/*BBTK_OUTPUT(TransferFunctionView,GreyLevel,"Greylevel related to the transparency",std::vector<double>,"");
BBTK_OUTPUT(TransferFunctionView,Value,"Value of the transparency in the transfer function",std::vector<double>,"");
BBTK_OUTPUT(TransferFunctionView,GreyLevelColors,"Grey level of the color in the transfer function",std::vector<double>,"");