(the list of most usefull CAD applications)

• Autodesk? DWG TrueView?
  

  View and convert .dwg and .dxf files with Autodesk? DWG TrueView? software.
  
  DWG TrueView is not only a free stand-alone .dwg viewer, but also convertor between DWG & DXF versions (It includes DWG TrueConvert).
  
  You can also use this free DWG viewer and convertor to plot and publish DWG files.
• DraftSight
  

  Free 2D CAD product to create, edit and view DWG files.
  DraftSight is easy to use and is available for professional CAD users, students and educators.
  DraftSight supports also SHX, LIN, PAT.
• nanoCAD
  

  nanoCAD is the latest free dwg based 2D/3D CAD for professional design and drafting..
  nanoCAD is developed to allow you to create drawings of any complexity in various industries such as mechanical engineering, building design, architecture, landscape design, etc.

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• Solid Edge 2D Drafting
  

  Whether you are using 2D across your company or for a specific 2D design process, Solid Edge 2D Drafting will give you an immediate advantage with production-proven capabilities including drawing layout, Goal Seeking, diagramming, and dimensioning. It is fully compliant with ISO, ANSI, BSI, DIN, JIS and UNI, and it's absolutely FREE to download and use.

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• SketchUp Make
  

  Model anything in 3D.
  Share and download models from SketchUp’s 3D Warehouse.
  SketchUp Make is not licensed for commercial work

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• Lee Mac Programming
  

  In our opinion - the best one resource of free LISP programs with highest quality for a variety of purposes
  Designed for AutoCAD and "AutoCAD Like" systems such as ZWCAD, IntelliCAD ...