Sandustry Filter Guide: Sort Pixels Without Jams

A Filter is a configurable Conveyor Belt. Matching pixels fall downward through it; non-matching pixels stay on the belt and continue in the belt’s travel direction.

Filter Modes

In Allow mode, select the one material that may fall through. Everything else continues along the belt. In Block mode, select the one material that must stay on the belt; other pixels fall through.

The Filter does not stop liquids or gases. It blocks the player under normal movement, although Hover lets the player pass through buildings.

Which Direction Does Material Go?

Think of the Filter as a belt with a downward outlet:

• A pixel that passes the configured rule drops below the Filter.
• A pixel that fails the rule continues horizontally like it would on a normal Conveyor Belt.

Always leave collection space below. A sealed or full outlet is a practical backup risk, so test the outlet before scaling the sorting line.

Density and Mixed Piles

Tall mixed piles can stratify by density. A lighter material sitting above a dense lower layer may never reach the Filter surface, so a correct rule can still appear ineffective.

The current Wiki records limited pulling from roughly one block (four pixels) away, but warns that this behavior is not completely reliable. Use shallow, controlled feed layers rather than depending on the pull range.

Why Filters Jam

The most important failure occurs when a material changes while it is passing through. Sand that touches Water becomes Wet Sand; Seed becomes Wet Seed. The new material may not match the original rule and can become stuck inside the Filter.

Check these causes in order:

1. The lower outlet is blocked or full.
2. The mixed input pile is too deep and density-separated.
3. Water or another reactant touches material inside the Filter.
4. The selected Allow/Block material is not the material currently present.

Move wetting and other reaction steps away from the sorting surface.

Lava Holding Use

The official Lava page describes filling a Filter with Cinder over a sealed lower block, then igniting the Cinder into Lava. This traps a heat source that can burn suitable material moving above it. Read the Lava transport guide before building this layout.

The current Research page lists the base Filter at Tier 1 for 250 Gold. This is a research unlock cost, not the cost to build one Filter. Advanced Filter descriptions conflict on whether multiple named materials can be selected, so verify that behavior in the current build.

Sources: Filter, Lava, and Research.