Creating Terrain From Scratch

This guide will continue the process of creating a new Terra config pack from the beginning with creating terrain.

If you haven’t already, please read the Config Development Introduction & Creating A Pack From Scratch for more information before continuing.

If you’re stuck or need an example, you can find reference config packs for this guide on the GitHub repo.

Setting up New Terrain

PROCEDURE

Tip

Throughout this guide, the /packs reload command can be utilized to reload config packs and observe changes live while in the world.

If Terra fails to reload after using /packs reload, then check the logs to troubleshoot the issue.

1. Add EXPRESSION sampler

The EXPRESSION noise sampler allows for configuration of an expression for sampler output with the capability of using functions in-built or user-defined along with other samplers within itself.

Open your FIRST_BIOME BIOME config in your editor of choice.

Add the highlighted lines below to replace the current terrain sampler with an EXPRESSION sampler.

first_biome.yml
 1id: FIRST_BIOME
 2type: BIOME
 3
 4vanilla: minecraft:plains
 5
 6terrain:
 7  sampler:
 8    type: EXPRESSION
 9    dimensions: 3
10    expression: -y + 64
11
12...

terrain.sampler consists of the nested parameters type, dimensions, and expression.

  • type - Determines the noise sampler that will generate the terrain

  • dimensions - Determines the amount of dimensional coordinates (x, y, & z) for input sampling

  • expression - The expression configured by the user to create sampler output for terrain

Terrain generation is determined by whether the expression output is positive or negative.

Positive output results in solid terrain whereas negative output results in air.

The sampler expression -y + 64 just takes into account the y-coordinate in particular for the moment.

The expression result will remain positive and generate terrain till the y-coordinate in the world reaches 64 leading to the expression looking like -64 + 64 equaling 0, which isn’t positive meaning no terrain generation will occur here and beyond 64.

Y-coordinates greater than 64 will result in a negative output like -90 + 64 equaling -26 that will result in no terrain.

The expression -y +64 results in perfectly flat terrain.

../../../_images/flat-terrain.png

Note

Documentation of EXPRESSION and other noise samplers can be found here.

Documentation of mathematical expressions can be found here.

Tip

You can add variables for expressions to use to allow for easier configuration.

first_biome.yml
1terrain:
2  sampler:
3    type: EXPRESSION
4    dimensions: 3
5    variables:
6      base: 64
7    expression: -y + base

You can even reference anchored variables not directly attached to the sampler.

first_biome.yml
1vars: &variables #variables anchored for samplers to use
2  base: 64
3
4terrain:
5  sampler:
6    type: EXPRESSION
7    dimensions: 3
8    variables: *variables #references previously anchored variables
9    expression: -y + base

2. Add sampler-2d

The expression -y + 64 results in perfectly flat terrain that will be used as the base terrain in which we’ll apply noise to using terrain.sampler-2d.

terrain.sampler-2d is recommended to configure alongside the terrain.sampler as it allows for easier adding or subtracting from the base terrain especially with being in 2D, which doesn’t account for the y-coordinate.

terrain.sampler-2d may be less performant, but results in more detailed terrain with being full resolution rather than interpolated.

Add the highlighted lines below to add the terrain.sampler-2d.

first_biome.yml
 1id: FIRST_BIOME
 2type: BIOME
 3
 4vanilla: minecraft:plains
 5
 6terrain:
 7  sampler:
 8    type: EXPRESSION
 9    dimensions: 3
10    expression: -y + 64
11
12  sampler-2d:
13    type: EXPRESSION
14    dimensions: 2
15    expression:
16
17...

terrain.sampler-2d will consist of the same nested parameters type, dimensions, and expression.

As terrain.sampler-2d is 2D, it will have 2 dimensions rather than 3 dimensions.

3. Add sampler for use

terrain.sampler-2d will now require an expression to influence the flat generation created by the terrain.sampler expression.

Either a cached noise sampler referenced through the pack manifest or one provided within sampler-2d.samplers will be needed in order to use it within the terrain.sampler-2d expression.

Add the highlighted lines below to provide a OPEN_SIMPLEX_2 noise sampler for use in the expression.

first_biome.yml
 1id: FIRST_BIOME
 2type: BIOME
 3
 4vanilla: minecraft:plains
 5
 6terrain:
 7  sampler:
 8    type: EXPRESSION
 9    dimensions: 3
10    expression: -y + 64
11
12  sampler-2d:
13    type: EXPRESSION
14    dimensions: 2
15    expression:
16    samplers:
17      simplex:
18        type: OPEN_SIMPLEX_2
19        dimensions: 2
20        frequency: 0.04
21
22...

sampler-2d.samplers consists of the noise samplers provided for use within the expression parameter.

Samplers are defined with a function name hand picked by the user with this case being simplex.

simplex will have to contain the parameters required for the noise sampler, which are dimensions and frequency.

frequency is explained in detail here.

4. Apply sampler to expression

The simplex sampler can now be utilized within the terrain.sampler-2d expression.

Add the highlighted line to the expression line below to implement simplex into the terrain.

first_biome.yml
 1id: FIRST_BIOME
 2type: BIOME
 3
 4vanilla: minecraft:plains
 5
 6terrain:
 7  sampler:
 8    type: EXPRESSION
 9    dimensions: 3
10    expression: -y + 64
11
12  sampler-2d:
13    type: EXPRESSION
14    dimensions: 2
15    expression: simplex(x, z)
16    samplers:
17      simplex:
18        type: OPEN_SIMPLEX_2
19        dimensions: 2
20        frequency: 0.04
21
22...

The terrain generates with 1 block elevation differences in response with simplex output.

../../../_images/bumpy-terrain.png

5. Adjust sampler-2d expression

The sampler-2d expression can be adjusted in a multitude of different ways to help achieve the result you terrain desire.

As the output range of OPEN_SIMPLEX_2 is [-1, 1], adding 1 to the simplex output within the expression will lead to the output range always resulting positive. With that, terrain will only be added on top of the base terrain without any subtraction as there is no possible negative output.

This is useful if you want terrain to be maintained above a certain y-level.

first_biome.yml
 1terrain:
 2  sampler:
 3    type: EXPRESSION
 4    dimensions: 3
 5    expression: -y + 64
 6
 7  sampler-2d:
 8    type: EXPRESSION
 9    dimensions: 2
10    expression: simplex(x, z)+1
11    samplers:
12      simplex:
13        type: OPEN_SIMPLEX_2
14        dimensions: 2
15        frequency: 0.04

Multiplying simplex with a value within the expression will lead to more hilly terrain as the simplex output gets increased along with expanding the range between the minimum and maximum output.

first_biome.yml
 1terrain:
 2  sampler:
 3    type: EXPRESSION
 4    dimensions: 3
 5    expression: -y + 64
 6
 7  sampler-2d:
 8    type: EXPRESSION
 9    dimensions: 2
10    expression: (simplex(x, z)+1) * 4
11    samplers:
12      simplex:
13        type: OPEN_SIMPLEX_2
14        dimensions: 2
15        frequency: 0.04

Attention

Make sure you put the addition operation within parentheses to make sure it happens before the multiplication operation.

The terrain elevation has some variety to it now. You can adjust the multiply value by increasing it to have bigger hills and decreasing it for smaller hills.

../../../_images/hill-terrain.png

Conclusion

This guide only covers the surface level capability in which you can configure terrain expressions.

There is limitless potential with more complex and intricate expressions that utilize various features such as built-in functions, user-defined functions, and multiple noise samplers to achieve terrain from that of simple landscapes to floating islands.

Reference configurations for this guide can be found on GitHub here.

Note

A useful tool for visually previewing your sampler configs is the Noise Tool that can be found and explained in more detail here.