How to dimension a spline in SOLIDWORKS

What if in SOLIDWORKS you need to model a wire, tube, or other path that has a predetermined length but you’re not sure exactly what shape it will take?  A spline might be the way to go, in preparation for a sweep, but did you know that you can dimension a spline’s length?  You can, and it’s just as easy as dropping a Smart Dimension onto the spline just as you would with a line.  This trick went unknown to me for years, until needing to apply it in the middle of an exam.  Then it was a matter of trying it out to see if it would work.

Just drop a Smart Dimension on the spline and set the length

Need to change the length?  Go right ahead and edit the dimension value:

Edit the dimension, and the spline changes length

For tube or wire, try setting the start and end location, direction, and tangency, and then removing all other spline points.  With the length set, it’s one way to fully define the spline.  A style spline is another way.

Spline fully defined