CAD tank/ fish room draw up?

ok I see folks build these mock CAD draw up designs for water stations, tank designs, and or fish rooms... where or rather what program are they using? and or what do you guys use to create these images. I need to do a draw up of a crazy system I have in mind and don't know where to start.





Thanks!


Here are some pics posted that I am referencing these draw ups too.


http://www.mbisite.org/Forums/tm.aspx?m=43725





any ideas?

 

ok, cool, I'll look into that.

 

right John?! lol. Unfortunately that's Tal's drawing of his fish room... and he verified he used google sketchup as well.... so, I'll look into it. I wish my drawing was done and good like that... lol. I'm still in the planning stages though!