One problem perhaps eternal for the beginners: how to create and annotate an image like this one. The image contains hidden lines specific to a 3D body represented in the plan. If the software is easy to use, and possibly free, the better.
Well that image isn’t very hard to draw*. But that seems to me a bit premature. I would first start by answering following questions:
Would you know how to draw that by hand. If yes then use a vector drawing application. Like Inkscape or Illustrator, or even something like vectorpaint. This is not much beyond lesson 3 into isometric drawing.
Do you know how to use TEX? If so consider using something like TIX. Or consider pylab/Matlab/Mathematica/R/etc. Again not a big deal.
Maybe a cad application? But most likely you may need 2 apps.
What do you consider easy? I mean there is no application that can just magically do that image with no training whatsoever.
Where do you intend to use the image?
* I could do the same in illustrator in less than 10 minutes.
Source : Link , Question Author : rosu_constantin , Answer Author : joojaa