Update (Oct. 15, 2023):
1) Fixed bugs to support Minecraft Snapshot 23w41a. Please update the datapack when upgrading your map for 1.20.3 snapshots. :-)

Introduction

Downloading and installing this datapack

Building the elevators

• Step 1: Obtain the banners.
  
  • There are 3 kinds of functional banners available in this datapack:
    a) Upward banners (Click HERE for how to craft it)
    b) Downward banners (Click HERE for how to craft it)
    c) Bi-directional banners (Click HERE for how to craft it)
  • You may check out the links above to craft them yourself. Or, if you're a map maker or a server op, you may also enter the following command to obtain all of them at once:
    /function ftmc_elevator:banners/give
• Step 2: Place the banners & glass blocks.
  
  • First, place one of the banners onto a wall in your building as the entry point. Then, place some glass blocks as the "tunnel" of the elevator, right above and/or beneath the position of the banner, as demonstrated in the following screenshot:
    
    
    
    
  • Optionally, you may want to also put some blocks around the other 3 sides of the glass blocks for decoration purposes.
    
  • And congrats! You made an elevator in your map! Let's try jumping or sneaking inside the elevators to test if it works. :-)
• Step 3: (Optional) Show the floor information.
  
  • If you are a map maker, you may want to let the elevator show some detailed information. You may place any kinds of pressure plates upon the glass block at the entry point(s), and then place a command block next to it, which can include the commands such as /title or /tellraw. The following screenshot demonstrates one way that works.
    
    
    
    
  • Tips: You may directly place pressure plates onto glass blocks on Minecraft 1.14+ versions, while it isn't possible to do the same way on Minecraft 1.13.x. For this case, you may still place it using a /setblock command.
    

• WELL DONE!! :-)
  
  • And, you may also want to check out this showcase video to check whether or not everything is working as expected. :-)
    

FAQs

1. I have placed a banner onto the entry point, and then properly placed the glass blocks above/beneath the location, but it still doesn't work.
   
   • Please check whether or not your banners were crafted in the correct orders and colors. You may refer to the links of functional banners provided above.
     
   • If you didn't place a bi-directional banner, then the entry point is expected to only work for a single direction depending on the arrow it shows.
2. I'm on a Spigot server that includes this datapack, and sometimes I was sinking into the ground when taking the elevator.
   
   • This issue has been fixed on Apr. 18, 2020. Please tell your server owner to update this datapack.
     
3. I realized that I was given a slow falling effect during an elevator ride. Is that what it is expected to work?
   
   • Yes! This mechanism was added on May 1, 2020 as a bug fix, and it is to prevent fall damages on multiplayer servers once it is laggy for you.
4. Is there any source code available for this datapack?
   
   • Yes! Please refer to this Github repository.