Example custom atlas using modded blocks from the ColorBricks16 mod.

The Atlas Creator Tool is the single unified tool for

being able to target a specific Minecraft version,
using a custom resource pack for textures and colour lookups,
importing custom blocks from mods.

How Atlasses Work

For OtS to work it needs to read the block data from the game. Minecraft versions, resource packs, and mods are all organised in similar ways. All assets are stored in the assets directory and followed by a namespace. For Minecraft assets that's the minecraft namespace and for any mod that's in the my_mod namespace.

OtS will scan each of these namespaces for model files and blockstate files and then in the tool you can choose which blocks to include. When the creation process has finished you will have an .ots_atlas file. This file determines:

What blocks OtS has available to it to use.
What the block textures look like.
How the voxel to block colour conversions are calculated.

Creating a Custom Atlas

1. Assets

First you need to upload a Minecraft version to get started.

If you choose an older Minecraft version then the block textures shown in OtS will be the textures at that point in the game.

Minecraft versions below 1.13 are not supported.

The uploaded .JAR files are not uploaded to a server and only exist on your local machine.

Optionally, upload a resource pack.

You can upload multiple resource packs and they behave similarly to Minecraft. If you add multiple then the bottom-most resource pack takes priority over the one below it and so on.

Optionally, upload a mod.

Similarly to resource packs, you can upload multiple mods.

For a mod to be compatible it must store its block data in the same format as the base game. For an pretend ExampleMod.jar, the mod's contents are expected to contain the following directories:

...

Some mods have asset dependencies from other mods. You must upload these mods also in order for OtS to correctly scan the game assets.

If your mod does not have a blockstates folder then no new blocks will be added to the atlas.

2. Blocks

In the 'Blocks' tab are all blocks OtS supports broken down into two lists of blocks:

The 'New Blocks' list contains blocks added in the uploaded version of Minecraft.
The 'Existing Blocks' list contains all the existing blocks in Minecraft.

If a block is not in either of these lists then it is not supported by OtS. If a block is enabled then it be added into the atlas. If a block is disabled it will be ignored.

You will most likely not need to edit any of the blocks inside the 'Existing Blocks' list.

OtS tries to automatically enable/disable blocks inside the 'New Blocks' list for you but may be incorrect so be sure to check this list before moving on.

When you are happy with your block selection, click 'Next' to move to the 'Models' tab.

3. Models

In the 'Models' tab is a list of blocks and their block models. If a block is in this list then OtS found multiple valid block models that this block could be rendered as.

For example, a minecraft:oak_log block could be rendered in Minecraft as vertical or horizontal. However, in OtS it must only be rendered either vertical or horizontal.

In this tab your job is to choose which block model to use for these blocks. OtS tries to automatically assign a model for you but this may be incorrect.

A block highlighted in

yellow

has not been assigned a block model. The selected block model for any block is highlighted in

blue

When you hare happy with your model selection, click 'Next' to move to the 'Download' tab.

4. Download

All that's left is to download your atlas! Make a name for your atlas and click the 'Download' button.

Using a Custom Atlas

You should now have an .ots_atlas file for your custom atlas.

FAQ

Why are X blocks disabled?

Some block types are automatically disabled. Here is a non-exhausive list of the blocks and the reason why they're diabled:

Leaves - Transparent blocks are not currently supported.
Glass - Transparent blocks are not currently supported.
Infested blocks - You probably don't want to build with these.
Non-waxed copper blocks - You probably want to build with the waxed variant to preserve the correct block colour.

Why is block X not in the list of blocks?

If a block is not in the list then it does not use a full-block model.

Why is grass disabled?

The colour of grass is dependent on its biome. Because of this, Minecraft stores its texture as greyscale so that it can dynamically tint it in-game. This confuses OtS so it is disabled.

Can I enable all the blocks in the list?

Yes. All blocks in the list can be used in OtS otherwise they wouldn't be in the list. However, Minecraft has a lot of block-specific behaviour so not all blocks should be enabled. For example, minecraft:tnt is automatically disabled because if by-chance it is placed next to a redstone emitting block then your build will not be happy.

Custom Atlasses