Problem with my bridge's pylons

[FVI]

Hello!
I'm drawing the textures of a plugin that also includes a bridge type.
I would really like my bridge to be an arch bridge like that of THEMAX, and in part I understood how, but to do so I need the pylons of my bridge to generate alternately (Practically a block with pylon, a block without and again with is so on.
Unfortunately the pylons are generated completely at random, and so I can't draw the arches.
Can someone help me please? Thank you!

The bridge on the left is mine, the bridge on the right is THEMAX's and I want to make a similar one.

[Hadestia]

Code: Select all

"pile distant": 0

[FVI]

Code: Select all

"pile distant": 0

Thank you!

[FVI]

Actually I don't know how to make the arches!!! I tried to send a pm to THEMAX but if someone else wants to help me any help is welcome.