What Rethinking Voxels works with.
| Platform | Java Edition |
|---|---|
| Loaders | Iris, OptiFine |
| Minecraft versions | 1.20.1, 1.20.4, 1.21.1, 1.21.2, 1.21.3, 1.21.4, 1.21.5, 1.21.6, 1.21.7, 1.21.8, 1.21.9, 1.21.10 |
Rethinking Voxels is a Java Edition shader for Iris that replaces Minecraft's standard lighting with voxel-based colored lighting and global illumination. Light from torches, lanterns, stained glass, and other sources bounces off nearby surfaces, tinting them with color and casting sharp, defined shadows. The shader is built on Complementary Reimagined and runs on Minecraft Java 1.20.1 through 1.21.10. This page also covers install steps, GI and shadow settings, and a full loader and version compatibility rundown, not just the download.
Colored Lighting and Global Illumination
The core technique is voxel-based light propagation: the shader samples world geometry at a voxel level to determine where light travels, rather than relying on Minecraft's flood-fill approximation. This enables several effects that standard shading cannot produce.
- Global illumination: light bounces off surfaces multiple times, filling areas with indirect color.
- Colored blocklight: torches, lanterns, stained glass, and other sources each cast their own color.
- Sharp block shadows: hard-edged shadows from all light sources, including sun, moon, and blocklight.
- Entity shadows: mobs and players cast shadows from every light source, not only the sun.
- Volumetric lighting: blocklight scatters visibly through the air in dim spaces and caves.
- Specular highlights: smooth surfaces pick up colored reflections from nearby light sources.
Colored Lighting in Caves
Caves have no sunlight, so torches, lava, and other blocklight sources do all of the lighting. Rethinking Voxels' global illumination lets that light bounce off cave walls and floors instead of falling off sharply at its source, filling nearby space with soft, colored ambient light. The result is caves that read as lit from several directions at once, rather than the flat, single-source lighting caves get without a shader.
How to Install Rethinking Voxels
Rethinking Voxels requires Iris Shaders. OptiFine is listed as a supported loader on the project page, but Iris is the primary and recommended pipeline.
- 1.Install Iris Shaders for your Minecraft version. Iris can be installed standalone or included in a Fabric modpack.
- 2.Download the Rethinking Voxels ZIP file from the Modrinth project page.
- 3.Open Minecraft and go to Options, then Video Settings, then Shader Packs.
- 4.Click Open Shader Pack Folder and move the downloaded ZIP into that folder.
- 5.Select Rethinking Voxels from the shader list and click Apply.
Performance and Settings
Global illumination and voxel-based lighting carry a significant GPU cost compared to simpler shader packs. Systems that run mid-range shaders at comfortable frame rates may see a noticeable reduction with Rethinking Voxels at full settings. The Iris shader settings menu exposes options for adjusting GI quality and shadow resolution, which can help on less powerful hardware.
Compatibility
- Loader: Iris (primary). OptiFine is listed on the Modrinth project page.
- Minecraft Java versions: 1.20.1, 1.20.4, 1.21.1 through 1.21.x.
- Client-side only. The shader does not affect server behavior.
- Bedrock Edition is not supported.
Questions about Rethinking Voxels.
6 questions
How do I install Rethinking Voxels?
Install Iris Shaders for your Minecraft version, then download the Rethinking Voxels ZIP from Modrinth. Open Minecraft, go to Options, Video Settings, Shader Packs, and click Open Shader Pack Folder. Drop the ZIP in, then select it from the list and click Apply.
Does Rethinking Voxels work with OptiFine?
OptiFine is listed as a supported loader on the Modrinth project page. Iris is the primary and recommended loader. If you use OptiFine, check the project page for any version-specific notes before downloading.
Which Minecraft version does Rethinking Voxels support?
Rethinking Voxels supports Minecraft Java Edition 1.20.1, 1.20.4, and 1.21.1 through 1.21.x. Check the Modrinth project page for the latest supported version list, as new minor versions are added regularly.
What does global illumination change in Minecraft caves?
In caves there is no sunlight, so nearby torches, lava, and other blocklight sources become the only light. Rethinking Voxels' global illumination lets that light bounce off cave walls and floors instead of stopping at its source, filling the space with soft, colored ambient light. The result is caves lit from multiple directions instead of the flat, single-source lighting vanilla Minecraft produces.
Is Rethinking Voxels good for low-end PCs?
No. Global illumination and voxel-based lighting are computationally demanding. Rethinking Voxels is aimed at systems with capable GPUs. If frame rate is a concern, a lighter shader pack is likely more appropriate.
Can I use Rethinking Voxels on multiplayer servers?
Yes. Rethinking Voxels is a client-side shader and does not affect server behavior. You can use it on any server that permits client mods, including public servers and Realms.
