With ELBOW you can’t control the end contours (same with CYLIND).
With TUBE you can and for the curve I have used REVOLVE where you can also control the start and end contours and surfaces with the mask values.
Barry.
Versions 6.5 to 22
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision M6800 - i7 4700MQ @ 2.40GHz, 16GB RAM, AMD FirePro M6100 (2GB), Windows 7 64bit