The direction and amplitude of lateralfriction1 and lateralfriction2

[tianbaoloin]

lateralfriction1 and lateralfriction2 are orthogonal to the normal force and are orthogonal to each other. Is there a definition of the direction of lateralfriction1 ? whether this direction coincides with the YZ plane of the Inertial coordinate system? In addition, I want to find the sum of lateralfriction, can i use the following equations to solve the sum of lateralfriction?
LF_Friction1_in_Inertial_coordinate = LF_lateral_Friction1 * np.mat(LF_lateral_FrictionDir1).T
LF_Friction2_in_Inertial_coordinate = LF_lateral_Friction2 * np.mat(LF_lateral_FrictionDir2).T
LF_Friction_in_Inertial_coordinate = LF_Friction1_in_Inertial_coordinate + LF_Friction2_in_Inertial_coordinate
If i wan to get the resultant external force of contact？ can i use the following formula？
LF_NormalForce_in_Inertial_coordinate = LF_NormalForce * np.mat(LF_ContactNormalonB).T
LF_resultant external force of contact_in_Inertial_coordinate = LF_NormalForce_in_Inertial_coordinate + LF_Friction_in_Inertial_coordinate
The normal force is defined in the inertial coordinate system, and whether the lateralfriction is also defined in the inertial coordinate system？