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
- DLSS Ray Reconstruction support
- DLSS Frame Generation support (experimental)
- HDR output
- Dynamic entity rendering in the ray-traced scene
- LabPBR-style material support, including toggleable subsurface scattering
- Deep settings UI: practically every renderer feature has its own sub-screen (upscaling, frame generation engine, ReSTIR anti-flicker tuning, water waves, POM depth/quality, clouds, exposure, terrain streaming...), and every sub-screen starts with a "Reset to Defaults" button — plus a global one on the hub — so experimentation can never strand you on a botched configuration
- Weather-driven lighting: rain and thunderstorms dim the sun/moon and darken the sky
- Volumetric 3D clouds in classic (vanilla-style boxes) or photoreal cumulus form, with adjustable thickness, opacity and cloud shadows, visible in reflections
- Dedicated Nether and End skyboxes
- OMM (Opacity Micro-Map) + SER (Shader Execution Reordering) optimizations
- Experimental NVIDIA SHaRC-style world-space radiance cache (Spatially Hashed Radiance Cache) to shorten noisy multi-bounce path tails — every shaded vertex warms the cache and back-propagates its light to earlier bounces, while diffuse vertices past the start bounce reuse the cached outgoing radiance instead of tracing on; toggleable with tuning options from the RT settings sub-menu and inspectable via debug view 13
- Vulkan graphics backend enabled
- A GPU and driver with Vulkan ray tracing support
- NVIDIA RTX GPU and supported driver for DLSS features
- 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.
- 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.
- 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.
- Multi-layer / cirrus clouds and cloud-shadow softening
- XeSS + FSR upscaling for non-NVIDIA GPUs
- LOD
- ReSTIR