From the drop-down menu "File" you can select the command Import general section from dxf file. So the below importation window allows you to import one or more polygonal concrete regions and (optionally) any number of bars with their own diameters. The imported section will be considered by program a general section typology.
The procedure to build the dxf file is specified in the information text box of the above importation window. If after the importation of file the section results very far from X,Y axes origin (as in the present example) you can shift the centroid to the origin X,Y axes by means of Shift Origin command in the general section window.
The dxf file of the simple polygonal section shown in the above figure is saved in the "\Examples" directory with the name "Sec autocad.dxf".