Is it possible to make a UR e-series follow a three dimensional toolpath. Some sort of G-code file you upload in Polyscope. I have seen this guide: UR+ | Universal Robots Toolpath Generator for SOLIDWORKS but that is basically only 2D.
The Autodesk Fusion 360 post processor allows for 5-axis tool path generation.
The HAL Robotics Framework for Grasshopper builds code export for UR robots into Rhinoceros and Grasshopper CAD packages so enables very easy spline manipulation and export/upload of URScript.