Truly impressive design! is this modeled by Rhino itself or T-spline was used?

It was done using old T-Splines plugin.

This is your design?

This model was received from former T-Splines plugin makers, so I suppose it is. Correct me if I am wrong.

Thanks for reply
i just want to know designer name.
because i going to remodel this chair in my next tutorial
and i want to give a Credit to designer in description.
please help me if you know designer name.
Thanks