For the moment you can't make with Moi that it's named RP (Realistic Photo) just a sort of NRP (No Realistic Photo)
It will be difficult to stay only in Moi if you want more ;)
But depend of what you want
Have you seen the poster of tut from Steph
http://moi3d.com/forum/messages.php?webtag=MOI&msg=999.1


all the 3 images are entirely Moi : that is sufficient for any technical documentation and you can colorize it if you want in any 2D progs
(these images are screenshot when you export your object in OBJ, you can ask to see it with some display: wireframe, shaded , shaded + edge
Just hide the grid and axes if you want
And before the save, normal screen appearence is some pretty too (some regulates colors pr others can be obtain manu Options)
you can press the key "Print screen" of your computer that copy the screen in the clipboard and past it in your favorite 2D prog for colorize or save image

For this http://moi3d.com/forum/messages.php?webtag=MOI&msg=1030.1
you must use one of this free one renderer http://moi3d.com/forum/index.php?webtag=MOI&msg=1035.4 or commercial else

Maybe the more easy to use for Realistic Photo is the free Kerkythea http://www.kerkythea.net/joomla/ but use a renderer is never really very easy as you must address a texture or a material to each different group of faces and create some many lights etc...;)

Another easy solution for No realistic image is use the free Google Sketchup
(yes another piece of Software) but this one is very simple and extremely powerful !!!
a convertor by Michael http://moi3d.com/download/3dmCurves2DXF.zip
who transform a Moi 3dm file format to Dxf format than you can reload in Sketchup ;)
format 3ds is also directly possible but have some limitation (65535 vertex or faces by objects)
Just import your model inside the free free Google Sketchup http://www.sketchup.com/ (last is version 6) and have fun rendering :)
(here not a Moi model but you can make the same! Amazing isn'it ? ) 3 just normal realtime renders in free Google Sketchup ! A true gem!