This was made with SolidWorks 2011 and is very, very easy! Its so easy that all you have to do is look at the pictures inserted below and create it.
For this project you will need:
A computer capable of handling SolidWorks and a MakerBot program
And also you creativity.
Simply sketch the drawing below in the second picture.
Create a revolve on that sketch.
Now draw all of the sketches for the ramp and the entrance.
Now do an extrude and filet for the ramp.
Cut extrude on the entrance.