Surfaces

I am not a skilled user of LibreCAD, and need to make surfices with lines and arks. May I have some advice

Hi,
I'm not a skilled user too . For the surface of a quadrilateral (a slightly twisted room) ABCD, I use these formulas :
 
2S = abs((xA-xC)*(yB-yD)) + abs((xB-xD)*(yA-yC)) Where xM,yM are the coordinate off M point...

I need  to copy manually each coordinate > Excel :( Is there a function for this ?

Or 2S = D * (H1 + H2) Where D is the diagonal BD and Hx the heights on D of A and C
I need to create 3 new lines and  > Excel ...

http://villemin.gerard.free.fr/GeomLAV/Carre/QuadAire.htm



If a programmer can look into :)

Sorry for my poor English


 

I am not sure what you mean with "make surfices".
 If you want to calculate an area, you can fill the boundaries with a hatch. When the hatch is created, the hatched area is indicated in the command line. It also works with arks. The boundaries have to be a closed shape.
 But unfortunately there is no way to ask the area of an existing shape.
There is Info - Polygonal Area, but this doesn't work with arks.