this is my ergo chair. ive made one like this in my advanced design class. conduit bending is quite difficult…lol
nice render but I think, that some people would be
scared to sit in the chare. 
I am sitting in a chair very similar right now. The only problem that I see with your design is, how do you sit or get up from your chair with the closed sides ?
Do you have such a chair %| ? I always wondered about them. Do your knees like the long hours of pressure? My butt take them very well (so far 
)
Anyway, I like the whole concept, and the nice rendering.
Arnaud
I’m also worried by being boxed in in that chair.
I have one and my knees are ok, although I’m a heavy man.
I took some time to get used to but I use it now without ever thinking about it.
This being said, I must confess that I don’t always take the canonic position…
Jean
yes i have made that chair. infact, it’s my computer chair im using right now. i have made some alterations to the actual one that i built. the knee support actually rotates on the bar, and it also has pegged holes that allow me to position it higher or lower on the front face. the actual seat also has a pegged slider. it can be moved closer or farther away from the knee support. and then there is the fact that i also have the seat portion rotatable. so that it can act as a normal chair as well. i made this in highschool this past year and it cost me about 300 dollars to make. but it was all worth it, because when i go to college for 3d animation, im gonna need something comfortable enough to help me last for the hours\days i will spend in front of my comptuer…haha.