An add-on for AUTOCAD or BricsCAD, which determines the unfolded section of one set of 3DSOLID, 3DMESH or 3DFACE entities and vertical planes passing through a 2D POLYLINE which may contain arcs, in XOY plane. Developed section is generated in the vertical plane passing through first segment of POLYLINE. The intersection is generated in the form of 3DPOLY entities, colored from 1 to 1, beginning with the color 1, corresponding to every vertical plane. The result is automatically generated in viewports ready for printing. You can set also the «concatenation precision» of the segments of intersection.