Curve cannot be bent using command

cannot bend.3dm (2.5 MB)

Hi guys, i have a problem on the simple command of “bend” on rhino. i have a curve that simply cannot be bent. when i create the spine with the bend command, and then proceed to bend it, the original curve simply remains unchanged.

please kindly help me have a look? really appreciate it.

yung to

The curve is a polyline with 75651 points. That may be too many points.

use the “rebuild” command. reduce the point count to 5000 or less. change degree into 3.
then you should able to use “bend” command.
cannot bend-1.3dm (573.6 KB)