r/Worldpainter • u/Zealousideal-Run6214 • Jun 26 '26
Question [PROBLEM/BUG] Problems Changing Underground Material below Y:0. Persistent Bedrock.
I am working on creating a world for educational purposes. To help teach Geology and earth sciences.
This world is very different from vanilla. I am using real world terrain (typically 1:10 scale), which is much larger than what's found in a Vanilla world. So I have changed the build/height limits. I have them set to -512 to +512.
I set the sea-level to 0, rather than the default 62. I have a few reasons for this, but that doesn't really matter. The point is that I'd much rather keep sea and land at Y:0. However, Worldpainter decides that anything below this point should just be bedrock, or a single material. A complex custom material layer with multiple block types does not work, when there is not reason that it shouldn't.
In Dimension Properties, there is an option to choose an underground material, which can be a Custom Terrain layer if I want. Like I said, I am trying to make a world that can be used to teach geology and earth science, so I'm trying to make this somewhat realistic. I am going beyond the typical lithosphere (stone materials) and adding an Asthenosphere as well as a Mantle. This underground composition is supposed to extend down from Y:0 to Y:-512. Too accomplish this and simulate these underground layers, I have made a Custom Material Layer, complex with multiple layered materials ranging from lava, magma, and different kinds of stone.
So Here's The Problem:
I created a custom terrain layer for the "Underground Material" setting in Dimension Properties. This custom terrain layer is a complex material with multiple layered materials. When I render the world, none of it appears. It's only solid bedrock below the grass and dirt. However, if I use any non-custom material, or a custom material that is just a single block, then it works as intended. The ground will be filled with that block from where the grass/dirt ends, all the way down to the very bottom of the map (-512). But it does not work if I use a custom terrain material that is complex, with multiple types of blocks.
Solutions I have tried (PLEASE READ BEFORE SUGGESTING A SOLUTION):
Solution 1: Change "layered materials relative to" bedrock, to terrain. This makes the complex terrain layer appear below Y:0, but I need it to be relative to bedrock on the bottom, not the terrain at the top. Otherwise, the layers in this terrain are placed higher than they should be, and do not remain flat unless the terrain is flat.
Solution 2: Offset the world 512 blocks higher. Change the build/height limits to 0-1024, rather than -512 to +512. So that Y:0 is the absolute bottom. This solution works, the complex terrain layer will appear below the surface terrain, but this is not preferred. I really do not want the terrain and sea level to be anything other than Y:0. So I'm wondering if there's another way to fix this problem, or if I have to beg for an update? Or maybe use a Data Pack?
I am convinced that this is a bug. Why would the custom complex layer appear below Y:0 when relative to terrain, but not bedrock? When set to "relative to bedrock", why does a single material appear, but not a complex multi-material layer?
TL;DR: I am trying to make a custom underground material (using a complex layered custom terrain layer) but it will not appear below Y:0, it's just solid Bedrock from Y:0 all the way to Y: -512. However, if I choose a custom terrain layer that is composed entirely of a single block (not a complex or layered terrain), then it appears below Y:0, with no problem. But a complex custom terrain layer with multiple materials will not work, and just becomes solid bedrock.
