Creating a profile graph from a 2D polyline

[CassandraKeyes]

I am doing a least cost path analysis and I wanted to create a profile graph of the path. I have converted the line to a vector. How do I convert the polyline to 3D? What is the best way to create the graph once I have done that? I used the Interpolate Shape tool and the Add surface information tool but when I try to create a profile graph with the 3D analyst extension the graphs are a straight line. 

[DanPatterson_Retired]

Interpolate shape... what options did you use

Create profile graph from 3d line.... did you use this?

And when you say the line was straight, can you screengrab the graph?