Software for re-structuring costs many thousands dollar
http://www.geometrysystems.com
http://www.geomagic.com

for 195 dollar you can import obj,3ds,stl in Moi, but attention, by Polygon a surface,
afterwards manual work is necessary,edge extract, re-draw to smooth surface

http://www.sycode.com/products/mesh_to_solid/index.htm