VectorEngineer Quick-Tools is a complete technical drawing and multi-purpose cad software system that offers all the features required to create accurate professional drawings, working drawings, designs, plans, layouts and diagrams in a quick and easy mouse driven windows environment. Its great for work, home, education and hobbies and best of all - its available for free, it's complete with no limitations, the free cad system has everything you need to produce any kind of drawing, its easy to use and is great practice until you go for the low cost upgrade option of the Pro Tools version.
Pro Tools features a larger feature set and has an isometric 3d design section to make isometric visualisations of your drawings.