Greeting,
Hi there,i am engineer and product design,i am have several experience engineer and manufacture,i am very interested with your project,i can help you for make 3d modelling and 2d drawing your bracket for connect chair to ceilling,and i can make gas studs for simulation how work,i use solidwork,i can start work right now if you award me,will send best result ,i can provide format file you needs,as STEP,IGES,DXF,DWG,STL and etc,hope we can work togheter,thanks Dedy.e