Auto CAD has been the industry standard since 1982 http://en.wikipedia.org/wiki/AutoCAD
This is a good place to learn the basics: http://www.mycadsite.com/tutorials/level_1/1-1.htm
Use this link to practice basic commands http://iit.edu/arc/workshops/pdfs/Introduction_to_AutoCAD.pdf
FREE CAD If you having a problem with official version: http://nanocad.com/
It is also good to think of ways to represent the world in architectural graphic terms:
Plan ( top View)
Elevation ( side view)
section ( cut away view)
How to set Line weights:: http://bestcadtips.com/plot-styles-questions-and-answers/
This is a good place to learn the basics: http://www.mycadsite.com/tutorials/level_1/1-1.htm
Use this link to practice basic commands http://iit.edu/arc/workshops/pdfs/Introduction_to_AutoCAD.pdf
FREE CAD If you having a problem with official version: http://nanocad.com/
It is also good to think of ways to represent the world in architectural graphic terms:
Plan ( top View)
Elevation ( side view)
section ( cut away view)
How to set Line weights:: http://bestcadtips.com/plot-styles-questions-and-answers/