About the "FillFromEulerAngles" method in the PC SDK

HI everyone ： I try to use EulerAngle calculation Orient by the "FillFromEulerAngles" method and I did a test. By the method of " ToEulerAngles()" convert a prepared quaternion to euler Angle. after that transform the EulerAngle into quaternion with "FillFromEulerAngles " method . It's a piece of my code: Orient ori_Base = new Orient(); Orient ori_Test = new Orient(); double x; double y; double z; ori_Base.Q1 = 0.707106781; ori_Base.Q2 = 0.707106781; ori_Base.Q3 = 0; ori_Base.Q4 = 0; ori_Base.ToEulerAngles(out x, out y, out z); ori_Test.FillFromEulerAngles(x,y,z); BUT .. "ori_Base" and " ori_Test" is not equal.... I think they should be the same Thanks for anyone's advice AND i 'm sorry for my bad english...