EX7.

โปรแกรมฟรีที่พอจะใช้แทน AutoCAD ได้

"FreeCAD"

              FreeCAD is a free and open-source (under the LGPLv2+ license) general-purpose parametric 3D CAD modeler and a building information modeling (BIM) software with finite-element-method (FEM) support.

Link Download  https://www.freecadweb.org/downloads.php