Filter Guide
The Filter is "a Conveyor Belt that can be configured to allow a certain pixels to pass through instead of carried onward" (sic — the wiki's own wording). One filter, one rule: Allow a single pixel type through, or Block a single type out. Everything else rides on like a normal belt.
Costs and Versions
| Research | Tier / Cost | What it does |
|---|---|---|
| Filter | Tier 1 — 250 Gold | Works like a Conveyor Belt but can allow certain elements to pass through |
| Advanced Filter | Tier 4 — 1,500 Gold | Filters multiple element types at once, including liquids and gases |
The basic Filter handles solids with a single-type rule; the Advanced Filter lifts both limits. It does not block liquids or gases passing over it, and blocks only the player.
How Allow and Block Work
Allow lets exactly one chosen pixel type fall straight through the Filter and be deposited below; everything else is carried onward like on a normal Conveyor Belt. Block is the mirror image: everything except the chosen type falls through.
Since v0.5.4 (August 16, 2026), editing is much less painful: "You can now press the filter overlay label or 'Edit last placed' to quickly change a filter without having to override and replace it," and the Allow/Block settings got clearer visual distinction.
The Density Rule (Why Pixels Refuse to Fall)
In a tall mixed pile, an allowed pixel at the top will not fall through if denser pixels sit below it. The exception: a pixel within 1 block (4 pixels) of the Filter can sometimes be pulled through denser pixels — but the wiki warns this cannot always be relied on.
The official strategy follows directly: "When filtering out pixels in a pile, it is best to filter out the densest pixels first as these will always be at the bottom of the pile and separate from the rest with no issue." To pull Gold out of Sand, Allow Gold — it is always at the bottom.
The Stuck-Pixel Trap
A pixel that changes type while passing through gets stuck: if Sand or Seeds combine with Water into Wet Sand or Wet Seeds inside the Filter, the result is neither allowed through nor carried onward, and must be removed manually.
Keep water away from filter lines carrying dry materials, or filter the water out first.
Power Move: The Auto-Burner Chamber
Placing a solid block below a Filter traps whatever enters. The wiki calls out the flagship use: "The primary use of this is to trap Cinders inside a filter and then ignite them to create trapped Lava that you can run Residue over to create an auto-burner."
That one trick automates the entire burning stage of the gold loop — the full build steps are on the Slag Burner page.
Densest first, always
Every clean split starts from the bottom of the pile. Chain Filters in density order — Gold (300) first, then downward — and each stage separates without fighting the physics.
Slag Burner Setups
The lava-trapped Filter auto-burner, step by step.
Gold Production
Where filters slot into the full loop.