Bug Report

The game crashes when you create or attempt to load a custom superflat world with no structures.

Steps to Reproduce (for bugs)

Create a new world with the following settings

• Superflat, Custom
  -Bedrock, 50 Stone, 3 Dirt, and Grass on top, no villages
• Game mode: Creative
• Generate Structures: OFF

You get the same crash if you try to load the world after you've crashed

Logs

• Crash Log: https://pastebin.com/DKrmBEXR

Client Information

• Modpack Version: 3.0.4
• Java Version: 1.8.0.51 (64 Bit)
• Launcher Used: Twitch
• Memory Allocated: 10 GB
• Server/LAN/Single Player: Single Player
• Optifine Installed: No
• Shaders Enabled: No

Unlikely that world types outside of Topography will be supported, but I'll leave this open in case.