2 answers

• 
  375Designs 12 months ago

  If you use Solidworks you can simply 'save as' 'IGES' or 'STEP'. Same for opening them, solidworks will run feature recognition, and then you can save it as a 'sldprt' or 'sldasm' file.

• 
  375Designs 12 months ago

  http://download.cnet.com/IGES-STEP-Converter/3000-18496_4-10974254.html
  Here's one but I suspect its just STP to IGS and vice versa