How to create a part from a 3d sketch in an assembly?

I want to create a part from a 3d sketch inside an assemblyfile. I have a structure that I have routed a 3d spline throughcertain holes. I want to create a part file representing conduitthat will be a swept profile along this 3d sketch. What is the bestway to do this in SW? I have Office Premium so I have the routingcapability. Should I consider this?

Maybe the graphic will give some insight to what I am trying to do.

Thanks,
JoelSolidworksParts And Features