The Stiffness Method with a UDL on a Pitched Roof

[Tygra_1983]

Hi there,

I am creating a portal frame model in SAP2000, and I am applying a UDL upon one of the rafters as shown below.

I am also using the stiffness method in MATLAB to validate my results from SAP2000. Thus far, I only have experience for models with orthogonal members and I am stuck on finding the values I need for the force vector for the portal frame's pitched roof (to apply in MATLAB). I have found the end reactions which for fixed ends in q*L^2/12 (moment) and q*L/2 (shear). But due to the comnplextry of having a sloped roof I am unsure how to apply these loads into the force vector in MATLAB. I have tried using simple trigonometry to find the vertical and horizontal components, but I am not getting the correct results.

This is my force vector that I have tried:

F = zeros(9,1);
F(1) = V/sind(alpha);
F(2) = V/cosd(alpha);
F(3) = M;
F(4) = 0;
F(5) = 0;
F(6) = 0;
F(7) = V/sind(alpha);
F(8) = V/cosd(alpha);
F(9) = -M;

Alpha = 2.864 degrees (the angle of the pitched roof).

If anyone here as good experience using the Stiffness Method any help would be much appreciated?