Caustica is an experimental ray-traced renderer for Minecraft 26.2's Vulkan backend. It replaces the vanilla world view with hardware ray tracing and NVIDIA DLSS features while keeping Minecraft's familiar UI and gameplay intact.
Caustica is early software. Expect bugs, missing visual cases, and frequent changes while the renderer is being built.
- Vulkan hardware path-traced world rendering
- Blue-noise sampling for faster convergence
- Denoiser choices: built-in temporal/spatial, NVIDIA NRD, BMFR, and Intel OIDN
- NRD methods: ReBLUR, ReLAX, and Reference
- Ray Budget with optional jittered native-pixel phases
- Experimental Distant Horizons integration: hybrid background and ray-traced LOD geometry
- Biome-aware volumetric clouds, cloud shadows, rain/thunder sky, and daytime fog
- Real refraction through glass and water (Fresnel + Snell's law)
- Real caustics from water and glass surfaces
- Accumulation mode for noiseless output
- HDR output
- Dynamic entity rendering in the ray-traced scene
- LabPBR-style material support
- OMM (Opacity Micro-Map) + SER (Shader Execution Reordering) optimizations
- Vulkan graphics backend enabled
- A GPU and driver with Vulkan ray tracing support
- A GPU with Vulkan ray tracing support (AMD RDNA 2+ or NVIDIA RTX)
- HDR-capable display and OS HDR mode for HDR output
- On Linux, an HDR-capable Wayland compositor and a native Wayland session for HDR output
- Install LabPBR resource pack like SPBR for better visuals
- Install Fabric Loader for Minecraft
26.2. - Install Fabric API.
- Put the Caustica jar in your Minecraft
modsfolder. - Launch the game with the Vulkan graphics backend.
- Open Video Settings to adjust Caustica's renderer options.
On Windows, build the mod without NVIDIA NGX/DLSS SDK files with:
.\gradlew.bat build -PnoNgx --console=plainThe built mod JAR is written to build/libs/.
For the best quality/performance balance, use:
- NRD: On
- NRD method: ReBLUR
- Realtime Denoiser Resolution: 80%
- Ray Budget: 1/2
- Ray Budget Jitter: Enabled
- Caustica is client-side only.
- DLSS Ray Reconstruction and Frame Generation require supported NVIDIA hardware and drivers.
- On Linux if Minecraft crashes on startup with stack overflow errors, try adding
-Xss2Mto the Java args to increase the stack size. - Use Java args to improve performance. Minecraft Launcher default:
-XX:+UseCompactObjectHeaders -XX:+AlwaysPreTouch -XX:+UseStringDeduplication -XX:+UseZGC - Frame Generation is experimental and needs to be enabled by modifying the configuration file.
- After changing Distant Horizons quality or distance settings, use Reload Distant Horizons Chunks in Video Settings. It refreshes DH's in-memory render cache and atomically rebuilds Caustica's RT proxy without deleting saved LOD or world data.
- HDR output requires an HDR swapchain and a correctly configured HDR display.
- When HDR is enabled on Linux, Caustica selects GLFW's native Wayland backend automatically. X11/XWayland surfaces generally do not expose the required HDR10/PQ format.
- If Minecraft falls back to OpenGL after a crash, re-enable the Vulkan backend before using Caustica again.
Caustica takes over the world renderer, so other mods that heavily modify world rendering, shader pipelines, post-processing, or the Vulkan backend may conflict. UI-only mods are more likely to work.
Caustica is not a finished renderer yet. Current work focuses on visual correctness, world coverage, stability, and making the SDR/HDR presentation paths behave consistently.
Caustica's project-owned source code and documentation are licensed under the GNU Lesser General Public License v3.0 or later. See LICENSE.md, COPYING, and COPYING.LESSER.
Release artifacts may bundle NVIDIA DLSS/NGX SDK components under NVIDIA's own license terms. See THIRD_PARTY_NOTICES.md.
- Nether/End sky
- Overworld weather: biome/location-shaped volumetric cumulus and storm decks, cloud-lit daytime fog, motion-aware animation and matching cloud shadows
- LOD
- ReSTIR