Autodesk Inventor

[#1]

I have a 3D part that produced from an assembly document. (pic.1)

How can I take the coordinates of the curve that is designed on the right surface (pic.2) in a .txt or better .xls file ? 

That curve I want to draw it in Excel.

It would be helpful if having vba programming solution.

[#2]

There are tools in existence which do this already, but so far as I know they all use sketch points & export them to csv.

You may need to place the points manually. I would imagine this would be extremely difficult to automate via the API given the number of potential variations from one set of geometry to the next. But I'm as far as it gets from being an expert in programming.

http://usa.autodesk.com/adsk/servlet/ps/dl/item?siteID=123112&id=17366925&linkID=9242018

http://modthemachine.typepad.com/my_weblog/2011/06/writing-work-points-to-an-excel-file.html

[#3]

You could try to iterate through all the surfaces and export thier vertixes with programming.