Robotics 2010 Design Challenge

I need help with the Robotics 2010 Design Challenges, it says I can get a free version of Autodesk® Inventor® but I would like to know the details about that if anyone knows: does it charge the professor? can I get an access code from a professor that isn’t mine? Is the free version just the trial? And if there are any other details that you think I should know let me know please.
Thank you

Edit: oh am I able to use Google sketchup Instead?

You can get a 1 year license through the autodesk student community It is the most recent edition and every year, you’ll be able to get another license as long as you are affliliated with a school or educational institution.

It is free and I am pretty sure that it needs to be made in inventor.