As of now, there’s no spline rendering possibilities in unreal for lines/splines/curves forcing DCC assets to be tubes geometries instead of a profile curve with a width attribute (like most renderers would support). Is there a plugin in développement that could fill that gap and make data transfers more efficients?
if you want tubes along a spline, just use the classical methods and examples for streets or waterslides. Unreal will deform the static meshes of your straight tube model into curves and connect them seamless.