Lisp to move block to another arc but keep the same legth between block

[cho.steven14]

Hello All,

Is there anyway to move block from one arc to another arc but still keep the arc length between block?

Attached the desired effect

[cho.steven14]

Something like that
So can we make it so it will only select block that the insertion point
intersect with the curve?
I try to change the _F to _X but not working
The rotation thing is not so important

[komondormrex]

well, did you check the update? i have already done that. command name changed also.

[cho.steven14]

Thank you @komondormrex for the soulution.

It really help alot in the job.