Path movement alternative for simple obstacle

[Atherton]

Hi
This is probably a really basic thing to do but I'm not quite sure where to start with it.

I want to create just a very simple obstacle for my platform game where a blade moves up and down between two points pausing momentarily before it reverses its direction. Initially I had hoped to just use a path movement for such a task but for some reason duplicates with the path movement tend to move out of sync when there is scrolling involved and it's kind of important that they aren't all doing their own thing so that I can design my levels to actually be passable.

Any thoughts or suggestions would be very much appreciated
Thanks

[Dynasoft]

Disable "inactive when out of frame" on the object, and they should all move together.

[Greg]

I would suggest using Alterable Values for that:

-Alterable Value A of Blade = 0 - Set Blade Y position to Blade Y-1
                                  Add 1 to Alterable Value B

-Alterable Vale B of Blade = 30 - Set Alterable Value A to 1

-Alterable Value A of Blade = 1 - Set Blade Y position to Blade Y+1
                                  Subtract 1 from Alterable Value B

-Alterable Value B of Blade = 0 - Set Alterable Value A to 0

If the Alterable Value A = 0, then the blade moves up, until it moves 30 pixels (the number of pixels it already moved is stored in Alterable Value B). Then the Alterable Value A switches to 1 and the blade starts moving down, until it moves 30 pixels back down, the Alterable Value A switches back to 0 and the movement loops.