How to work with STEP files
Look here this might help.
From another Grab-cad user:-
fastest way to convert .stp file to .catpart file:
- Open .stp file
- Save as CatProduct
- Select the object that will change to an independent
- Choose TOOLS > GENERATE CATPART FROM PRODUCT > OK
- Save as CatPart
- DONE :)
You can use most measuring tools your CAD program provides. when you open a step it normally makes a copy in your default cad format. but without the data that was used to make the originale part. however you make new sketches by projecting the original surfaces
Ignazio: In order to work with STEP files, you need some software: Either a STEP Viewer, or CAD with the STEP converter capability. STEP Viewer software is cheaper and will allow you to at least open, measure, and print the STEP data, but not modify it. You need a CAD software to convert and modify the STEP data.
Any autodesk software will open a step file.
You will be asked what to do when you open it.
Choose convert model to one body (if it is one part) or to more parts.
Next go to File>Export>CAD format and chose cat part.
Then name it and open the catpart in CATIA.
Hope it helps.