Guide
SEUS PTGI on a Mac, and the nearest thing I can offer
By Ryleigh Newman · Published · Updated
SEUS PTGI is, in its maker's words, an experimental version of SEUS with a custom software implementation of ray tracing that does not need an RTX card, made to be used with OptiFine (read on 2026-09-19). The newest PTGI download on its site is HRR Test 2.1, dated 17 December 2020, and OptiFine's newest build is a preview for Minecraft 26.1.2, so on any machine, Mac or not, PTGI is a pack for older versions of the game. Rockstar Shaders is not path tracing and does not pretend to be. It is a Fabric mod for Minecraft Java 26.3 on Apple Silicon Macs whose ray tracing runs in Metal: exact sun shadows, sky visibility, one bounce of global illumination, water reflections and fog occlusion.
I made Rockstar Shaders on a Mac, for a Mac, because a Mac can trace rays in Metal and no shader pack could reach it: packs are GLSL run by a loader on OpenGL. This page says what PTGI is, what stands between it and a Mac on 26.3, and exactly what my trace does and does not do.
Download free (1.0.0) Modrinth (pending)Minecraft 26.3, Fabric, macOS on Apple silicon. Install guide. Releases and bug reports on GitHub.
Side by side
| SEUS PTGI | Rockstar Shaders | |
|---|---|---|
| What it is | A shader pack by Sonic Ether, in the OptiFine format | A Fabric mod with its own renderer; the shaders and a Metal side-car ship inside the jar |
| How it traces | A custom software implementation of ray tracing, in its own words; path-traced global illumination and ray-traced reflections | A Metal side-car reached through VK_EXT_metal_objects: sun shadows, sky visibility, one-bounce GI, water reflections, fog occlusion |
| Loads through | OptiFine, or the legacy GLSL Shaders Mod | Fabric Loader 0.19.5 or newer and Fabric API |
| Newest listed build | HRR Test 2.1, 17 December 2020 | 1.0, for Minecraft 26.3 |
| GPU stated | Does not require an RTX graphics card | Apple Silicon (M1 or later); a Metal device that supports ray tracing |
| Operating systems | Not stated | macOS on Apple Silicon only; Windows, Linux and Intel Macs are not supported |
| Tested on | Not stated | One machine, an M4 Max with 48 GB |
| Price | Free, through posts from its author | Free, from rockstarshaders.com and GitHub (Modrinth pending) |
SEUS facts read on 2026-09-19.
What SEUS PTGI is
SEUS, Sonic Ether's Unbelievable Shaders, is a pack to be used with OptiFine or the legacy GLSL Shaders Mod, by its site's own description. SEUS Renewed is the rasterized line. SEUS PTGI is the experimental line: PTGI stands for Path Traced Global Illumination, its main feature, and it also carries ray-traced reflections. The tracing is a custom software implementation inside the shaders, which is why the site says it does not require an RTX graphics card. Its author says most of the development time lately goes into PTGI, and that PTGI is now free. The site's download table lists PTGI HRR Test 2.1 from 17 December 2020, E12 from 8 January 2020 and E11 from 6 December 2019, each linking to a download post on another site; those posts would not load for me, so the version list is the site's own. There is no mention of macOS, Windows, Vulkan or OpenGL anywhere on it. All read on 2026-09-19.
It is the pack most people mean when they say ray tracing and Java Edition in one breath. I am not going to pretend the one I made does what it does.
What stands between PTGI and a Mac on 26.3
Three things, none of them about Macs in particular. First, the loader: PTGI is written for OptiFine, and OptiFine's newest download on 2026-09-19 was a preview for 26.1.2, with 1.21.11 the newest release build, while Minecraft 26.3 shipped on 15 September 2026. Second, Iris: it lists 26.3, but an issue on its tracker opened in June 2025 reports PTGI failing to compile on 1.21.6 with Iris 1.9.0, and it was still open with no maintainer reply visible when I read it. Third, the API: OptiFine and Iris run on OpenGL, which on a Mac tops out at 4.1 by Apple's own table, and which Mojang wrote in February 2026 it will remove from the game once Vulkan is stable.
So the honest answer to the search is this. On a game version that OptiFine reaches, PTGI may run on a Mac, at whatever speed a software path tracer gets from OpenGL 4.1 on Apple's GPU; I have no number for that, because I have not tried it. On 26.3, it does not run through OptiFine, because there is no OptiFine for 26.3.
What ray tracing means in Rockstar Shaders
MoltenVK, which runs Vulkan on a Mac, exposes no VK_KHR_ray_query; the mod expects that and logs it at start-up. So the tracing is not Vulkan. A native Metal side-car, libvrt.dylib and vrt.metallib packaged inside the jar, takes the Metal device out of the game's Vulkan device through VK_EXT_metal_objects and traces the game's own chunk vertex buffers. Leaves are alpha-tested in the trace through an intersection function that reads the exported block atlas. From that one structure come exact sun shadows, sky visibility, one bounce of global illumination, the sky and sun visibility of every fog froxel, and water reflections: one mirror ray per water pixel with roughness cone jitter, block and sky light at the hit, and clouds along the reflected ray. Metal and ice reflect the same way.
What it is not. It is not a path tracer: one bounce of GI, not many. Dynamic lights, the held torch and the burning mob, cast no shadows. Colored block light comes from a camera-centerd volume of emitter radiance, and it leaks through thin walls; that is a known limit. Glass panes do not request a traced reflection by default. Without the side-car, on any machine where one of its gates fails, the mod still renders, minus all of the above, and enclosed spaces look veiled. The settings are on Lighting and Shadows and Reflections and Materials.
Why the trace is on by default
Because it is cheaper than not tracing. At one pose on the M4 Max, everything on took 27.9 ms a frame; ray-traced shadows off took 29.7, ray-traced reflections off 29.3, ray-traced fog off 29.3, and all three off 29.5. Each fallback, the rasterized cascades standing in for the traced sun, the screen-space trace alone standing in for the mirror ray, the untraced froxels, costs more than the trace it replaces. The three traces are restart-only toggles, Ray-traced shadows, Ray-traced reflections and Ray-traced fog, and I leave them on. The four rasterized shadow cascades stay in the pipeline either way, in a 4096 or 2048 atlas.
The Metal traces run outside the pack's own GPU timers; at my window size the shadow and sky trace together were 3.8 ms. The Show pass timings overlay lists every other pass in milliseconds, live.
The rest of the picture
Ray tracing is one subsystem of eleven settings categories. The sky is an analytic atmosphere with the original square sun, a Milky Way, an aurora over cold biomes and the original blocky clouds, lit and marched. The water is its own engine: a wind-driven wave ladder limited by how much open water surrounds each point, a simulated ripple field 32 m across for rain, boats and the player, shore surf, falling water as a clear tinted column, caustics and underwater god rays. Fog is a froxel march. Foliage waves, leaves whiten in snow, the pack draws its own rain, snow, puddles and lightning. Connected glass and sandstone, Better Grass and the OptiFine resource-pack formats are read natively. An extended horizon keeps seen terrain on the skyline out to 64 chunks by default. The frame ends in temporal anti-aliasing, auto-exposure, bloom, depth of field and AgX grading. Every page of it is under help.
What it costs, and what is wrong
Every number is from an M4 Max with 48 GB at the resolution it names. At a sunset bay, looking down at the water, at 1708x960, 34.3 to 35.7 ms a frame after the last performance pass; at my window, 1706x1966, 46.0 to 46.5 ms. Render scale 75%, the default, took that pose from 44.98 to 33.95 ms. An M1 will be slower, by an amount nobody has measured. It is version 1.0, free, measured on one machine. Your own first-person shadow does not appear yet; shore foam and spray are compiled out at the defaults; ground the horizon generates on demand is not saved; the ripple field restarts from flat when settings rebuild the renderer. Windows, Linux and Intel Macs are not supported and not tested, and there are no dates for anything.
Which one to pick
If you want path-traced global illumination and you have a machine and a game version that OptiFine reaches, PTGI is the pack, and it is free from its author. If you are on an Apple Silicon Mac on 26.3 and you want shadows, sky light, one bounce of GI and water reflections traced on the Mac's own GPU, inside a renderer built for the game's Vulkan backend, and you can live with a 1.0 release, that is what this is. The wider question of ray tracing on a Mac, including Bedrock, is on ray tracing in Minecraft on a Mac, and the install is a jar and one Vulkan switch, on the install page.
Download free (1.0.0) Modrinth (pending)Minecraft 26.3, Fabric, macOS on Apple silicon. Install guide. Releases and bug reports on GitHub.
Related
Sources
- https://www.sonicether.com/seus/ (read 2026-09-19)
- https://github.com/IrisShaders/Iris/issues/2791 (read 2026-09-19)
- https://modrinth.com/mod/iris (read 2026-09-19)
- https://irisshaders.dev/ (read 2026-09-19)
- https://optifine.net/downloads (read 2026-09-19)
- https://support.apple.com/en-us/101525 (read 2026-09-19)
- https://www.minecraft.net/en-us/article/another-step-towards-vibrant-visuals-for-java-edition (read 2026-09-19)
- https://minecraft.wiki/w/Java_Edition_26.3 (read 2026-09-19)
Questions
Does SEUS PTGI work on a Mac?
Its site does not say. It is written for OptiFine, whose newest build on 2026-09-19 was a preview for Minecraft 26.1.2, and it runs on OpenGL, which Apple's table caps at 4.1 on every Mac. On a version OptiFine reaches it may run; I have not tried it and have no frame rate for it. On 26.3 there is no OptiFine to run it.
Is Rockstar Shaders path traced?
No. Its Metal side-car traces sun shadows, sky visibility, one bounce of global illumination, water reflections and fog occlusion. One bounce is not path tracing, and I do not call it that.
Does Rockstar Shaders need an RTX card?
No, and it cannot use one. It runs only on Apple Silicon Macs, M1 or later, and traces through Metal on the Mac's own GPU. It has been run on one machine, an M4 Max with 48 GB.
Is it hardware ray tracing through Vulkan?
No. MoltenVK exposes no VK_KHR_ray_query, so the tracing is Metal, reached from the game's Vulkan device through VK_EXT_metal_objects. Whether that is faster than not tracing was measured: everything on was 27.9 ms a frame and all three traces off was 29.5.
Can I run SEUS PTGI and Rockstar Shaders together?
No. PTGI needs OptiFine on OpenGL; Rockstar Shaders needs the Vulkan backend and loads no packs. One or the other per launch.