Curtain wall frame scheduling.

[Botonis]

I have a simple curtain wall that looks like a pergola with wooden beams on the bottom and vertical metal beams on top. The edge angle is set to manuall so all the beams look continous without gaps at the intersection points. 

When scheduling the curtain wall frame classes the results are not correct . Even if the frames look correct in the 3d without gaps, the lenght of the wooden frame with the smaller priority, is reduced by the width of the metal frame.

If you have a grid this is repeated as many times as there is an intersection, so the error is enlarged. 

This is because the calculation considers the length of the  grid line and not the 3d object itself.

Is there a way to overcome this limitation without manual processes.....? 

In the picture above you see the bottom frame (grey) calculated correctly 1m because I have assigned a higher priority.

The above black frame (lower priority) in the 3d is 0,18m but it is calculated 0.05m because this is the gap according to the scheme.

Ι used an expression for the current frame class, which adds the miising lenght but this is not practical. The element 3D lenght for frame classes does not give a result.