What type of computer graphics are you doing? I render with Poser everyday creating 3D images. Anything from simple objects to complex complete human and non-human gaming characters. You can download a free-trial to work with to see if it's something of interest. If you don't want to do that you can use Daz Studio which is free
Daz Studio:
http://www.daz3d.com/i/software/studio?_m=d
Poser 7 Trial:
http://my.smithmicro.com/downloads/index.html
If you are looking for more illustrator type programs - I found lots of them one day while writing an article for my blog. I cannot endorse them as I haven't tried them personally.
Inkscape:
http://www.inkscape.org/
DrawPlus:
http://www.freeserifsoftware.com/sof...us/default.asp
Hope I helped a tad. Good Luck!