How could I edit several lines or curves at once?

Here’s a vedio I came across the other day, BUT at 00:04:02, after doing some “Mirror” adjustments, he just could edit all four curves simultaneously.

Is there anybody telling me how to do this please?

Thank you all


he’s using Record History feature

This will create a parent-child relation. The original shape is the parent and the mirrored one
Is the Child. So when you modify the Parent you will be affecting the Child object. But not
The other way around. Actually, if you try to modify the Child, Rhino will warn you that this will break
The relation between them.
You can turn this feature ON permanently by right-clicking and choose Always Record History,
Or you can use it only on specific operations.
In the case of this tutorial video, you can type the Mirror command and press Enter, then click Record History,
Now choose the shape and do the Mirroring. After finishing the operation the Record History will be OFF again.