Is there anyway to connect or fillet polylines that were drawn in different UCS's?

You wouldn't be creating a 3D piping layout by any chance?I'm not sure it can be done but if someone knows a way of doing it I'd welcome the news as well.

That is exactly what I am doing, and short of exploding all of my polylines and filleting the regualr lines and then sweeping all of the lines, I don't know of a better way.

Hello dlmiller1999, it's possible to draw a 3D polyline ( command _3DPOLY ) but in that command it's not possible to include arcs and lines like with the 2D polyline ( by typing inside the command at any time A for arc and LI to go back to line ).
Unfortunatly, it's not possible to connect 2 2D polylines in different UCS as you were saying ( command PEDIT ).
 
When doing a 3D polyline it's possible to extrude a profile along that polyline ( provide the polyline is not closed ) but as you don't have arcs it may not interrest you ( this is working with my AutoCAD Mechanical 2012, verify with your release ).
 
On the old releases it was not possible to extrude a profile along a polyline if the radius were shorter than the radius of the profile to be extruded, now it's possible, verify with your AutoCAD 2013.

From www.ant-ares .de you can download PEDIT3D for AutoCAD (or Bricscad)RegardsJochen