Extruding Handrail Problem

I am still confused as to how the extrude and sweep commands work. I have a stair which needs a handrail to wind it's way up to a landing, turn 90° then turn 90° again and then continue up the next stringer.

So I build myself a 3dpolyline which traces the path of the top of the round tube. I draw a circle at one end of this 3dpolyline and position it so that the top quadrant is on the end of the 3dpolyline. Then wheter I use extrude or sweep the handrail gets drawn. The problem is that along the first run of the stair the circle follows the path below the 3dployline. But then when it turns the 1st 90° corner, the circle is now located with the quadrant on the side of the circle along the line. What I need is for the circle to extrude always below the 3dpolyline I've created.

Can anyone steer me clear on this?

Sweep Handrail Problem.dwg

What I need is...

Autodesk Inventor.

Perhaps there is a problem with your 3Dpolyline. I was able to accomplish the task using a drawing of my own. I did it using vanilla 2009. My handrail was one continuous 3Dpoly. So, please, do not run out and buy Inventor just yet even if it would solve your problem. I think you just overlooked something.

Better go buy Inventor.

Bill, I was able to duplicate your problem. I downloaded your drawing and noticed you had something I didn't in my handrail and that was the two small vertical pieces. As soon as I introduced them into the mix I managed to get the same results as you. Go figure.

My handrail had a total of eight direction changes. Three of those were vertical risers. Of the total sections of handrail, three had the path to one side and not at the top. You'll have to break the handrail up to get the desired results.

Could I ask three questions:

1. If someone were to take the 3DPOLYLINE I created and import it into Inventor, then sweep the circle pattern along this path, would they be able to save it in a format that I could import back into AutoCAD 2010?

2. If the answer to #1 is yes, could someone assist me with this?

3. Will Revit do this type of sweep or extrusion?

I seem to have found the solution to this. My goal was to create the 3DPOLYLINE along the top of the handrail. But that caused the problem above. When I created the 3DPOLYLINE to track the centerline of the handrail pipe I got what I was after. At least for now this looks like the solution because I cannot afford a copy of Inventor.

Did you manage to get it sorted ? let me know how you got it please !