to join polylines, they all have to be at the same elevation. Therefore, you need to make sure you are drafting your polylines at the same elevation by avoiding snapping to the z coordinate of the objects you are snapping to. OSNAPZ is a system variable, when set to 1, that automatically filters out the Z coordinate of the objects you snap to but assigns the elevation set in the drawing.
if the polylines you already drew, are not flat at 1 elevation than you can flatten them with the FLATTEN command, then join them.
pipes that I'm modeling are in specific coordinates.. flattening is not an option .. i"m resolved to ask the client to export from CATIA in different ways .. from what I've researched its similar to solid works yet different... trial and error i guess.. was hoping for a quick fix.
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