Faster Iris Shadow Mapper [FISM]
Slightly improves the speed of Iris' shadow mapper. Built-in in Iris since Iris 1.11.2
- Loaders
- FabricNeoForgeForgeQuilt
- Downloads on Modrinth
- 918K
- Followers on Modrinth
- 89
- versions
- 35
- Updated
- September 20, 2026Sep 20
- Published
- in 2026
At a glance
Install in the game only; not needed on the server
⚠️ This has been included in Iris 1.11.2, it is now only useful for older MC versions or for forks like oculus ⚠️
Faster Iris Shadow Mapping is a really lightweight mod that prevents unneeded things from rendering during the shadow pass.
This project does not replace Iris, both needs to be used at the same time for it to work.
This mod also works with oculus.
How it works
During the shadow pass, for opaque models, the color of the model won't have any visual change, a blue car and a red car both cast the same shadow, no matter their color. So what this mod does is it prevents things like the text on signs, the banner patterns, the enchantment glint etc from rendering during the shadow pass. It only improves performances when some of those are visibles.
Performance showcase
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- +10% FPS
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- +50% FPS on average
- +1000% FPS on 0.05% low
- The signs have text on them but on the other side
Modpacks
Feel free to use this mod in your modpacks without asking for permission.
FAQ
How to install Faster Iris Shadow Mapper [FISM]?
Install Fabric for your Minecraft version, download Faster Iris Shadow Mapper [FISM] for the same version and loader, put the file into the mods folder and launch the game with the loader profile.
Which Minecraft versions does Faster Iris Shadow Mapper [FISM] support?
Faster Iris Shadow Mapper [FISM] has builds for Minecraft 1.20.1, 1.21–26.3.
Is Faster Iris Shadow Mapper [FISM] needed on the server?
Client only — no need to install it on the server