Indexing images for The Sandbox implementation

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Oct 25, 2023

In this documentation you will learn how to implement images in great detail in a fast way within The Sanbox

The Mission

One of the most common problems we encounter when working in The Sandbox is the resolution at which we work.

Generally, the most common resolutions are 32x32, 64x64, and so on.

With this in mind, our goal is to be able to extract as much detail as we can from a larger, more complex image (e.g. 1024x1024) and implement it within the engine.


  • Photoshop
  • MagicaVoxel
  • VoxEdit
  • The Sandbox Game


The process is relatively straightforward but there are many things to keep in mind. The workflow (simply explained) is as follows.

Search for images that we want to index, their format has to be .png (We will use search engines like Pinterest).

It is easier to get good results with simple textures

In case it is not a format like .png, we will transform the image to these formats.

We check that the images are not copyrighted images.

After this, we will open Photoshop and load the image.

We can use other programs that can also index colors

The resolutions at which The Sandbox works natively are 512x512, 256x256, 128x128, 64x64, 32x32.

For this example we will use 256x256.

To reduce the size we will use "Image Sice".

Here we will give the size we use

In case the image is not square, uncheck the chain icon to give it the correct size.

The default resolution is 96 px

Once we have the size we are going to use, we will index the image. To do this, go to the “Mode / Indexed Color” section.

By using 8bits, we will greatly reduce the amount of information we work with without losing much quality

One thing to keep in mind is that the image has to be 8Bits/Channel. In case it is 16 bits or 32 bits, we will select 8 Bits.

This change has hardly any impact, especially considering the final sizes and qualities we are looking for.

Once here, the "Index Color" window will appear.

Here you can find the number of colours in that image, what kind of palette it uses, as well as the option to preserve the exact colours of the image in case you need them.

We can use " Preserve exact colors", but for this example it is not necessary
It is usually used for complex images

To index the image correctly, select "Local (Percentual)" for correct indexing.

We can use other palettes, but the one that always works is "Local (Percentual)"

Generally the best quality is found in 64 colours. We can use more, but that number is more than enough.

It is always better to keep as many colors as possible, but it depends on the complexity of the image

Now, with the correct amount of colours, we will go to the "Custom" section.

Here we can check the number of colors and see if there are any we don't need

A new window called "Color Table" will open.

Here, we will check that the colours are similar to the original image, if it is correct, we will click on save.

Here we can load or save palettes, we can use it to enter our own color palettes

This will generate a document with the extension ".ACT". This palette is the one we will take to any program that can use it. In this case, we will use it in MagicaVoxel.

This step is very important if we want to keep palettes or modify them in the future

This process is the most complex of all. But it is finished! Now we can move on to the fun part 🐒

The best scenario in which we can make use of this image is in MagicaVoxel. In this program we will generate texture-based objects with indexed colour palettes.

To make use of .ACT it is as simple as dropping it into the palette section.

Basic palette
Custom palette

To use the image as an object, it is as simple as dragging it to the centre of the program.

It is important to check the texture before confirming that it has been applied correctly

In case we do not import the colour palette before including the image, it will appear incorrectly.



This is just a short introduction to image indexing. The most interesting thing about it is that we can scale it to infinity.

We can combine images, create trim sheets and even create objects directly in Photoshop / Substance Designer and include them in our Voxedit projects.

One very interesting thing about this technique is that it allows us to extrapolate any trim to create complex objects from these indexed textures.

In the future, I will create more documentations talking about this topic and I will link them to this publication, as they are two things that go hand in hand.

Substance Painter
The Sandbox
PJ Martínez
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