Reverse engineering a model from the internet

hi there! I’ve been asked by my job to convert a file of a chair into a workable, printable file. I’ve been trying for days to fix the model, even trying to build it from scratch but I keep running into problems and failing.

I’ve managed to convert the mesh into polysurfaces but I run into problems when trying to offset of the shapes of the objects look incorrect on rendered mode.

I’m not very good at using rhino so any tips would be really appreciated.

I’ve attached the file below for anyone who might want to take a look.

REDONDA_slitta_3ds.3ds (17.8 MB)

thanks so much!!