Filters in Sandustry

Route one material with a Basic Filter, handle multiple materials with an Advanced Filter, and fix leaks, stuck items and wrong-side routing.

Quick answer

1 material: → Basic Filter
Multiple materials: → Advanced Filter
Wrong route: → Check Allow / Block

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Build a Filter rule

Set the Filter, mode and materials. The preview shows expected routing from the current rule — pile depth and conversions can still change what you see in-game.

1. Filter type

2. Mode

3. Material

4. Result

Allow Gold

Selected materials take the filtered route. Other materials continue on the main route.

Mixed input

GoldSandResidue

Filter

Match → filtered route

Gold

Other → main route

SandResidue

Actual flow can still be affected by pile depth, material transformation or another material displacing pixels around the Filter.

Allow vs Block

Allow

Selected material matches the rule.

Example: Allow Gold

Block

Selected material is excluded by the rule.

Example: Block Gold

Not sure which one to use? Build the rule above and check the routing preview.

Which Filter should you use?

Start from how many material rules the same junction needs. The table below is the detailed comparison.

How many material rules do you need?

One: → Basic Filter
More than one: → Advanced Filter
Need logic or control behavior?: → Advanced Filter

Basic Filter

One simple material rule

Advanced Filter

Multiple material rules

Feature	Basic Filter	Advanced Filter
Multiple selected materials	No	Yes
Solids	Yes	Yes
Liquids	—	Yes
Gases	—	Yes
Best use	One material split	Several materials on the same junction
Research	250 Gold	1,500 Gold

Advanced Filter is a separate building. Unlocking it does not turn existing Basic Filters into Advanced Filters.

How do Sandustry Filters work?

A Filter evaluates the material against the active rule. Matching and non-matching material are then routed differently.

Mixed input

GoldSandResidue

Filter

Match → filtered route

Gold

Other → main route

SandResidue

Try it

Gold + Allow

Easy to miss

Did you know Filters have a Wall Mode?

Select the Filter and press R to switch between Conveyor Mode and Wall Mode. The available hotkey is also shown in the lower-left game controls.

Select Filter → press R → Wall Mode

Common Filter setups

Load a working rule into the Builder, then copy the layout if you need the surrounding line.

How to filter multiple materials

A Basic Filter needs one rule per material. An Advanced Filter can send several selected materials down the same filtered route.

Advanced Filter example

Mixed input

Gold

Wet Sand

Burnt ResidueSand

Advanced Filter

Match → filtered route

Gold

Wet Sand

Burnt Residue

Other → main route

Sand

Reliable Gold Filter setup

Gold is the densest useful pixel in a mixed Wet Sand pile, so it sits near the bottom and is the first material worth filtering.

Gold Filter preset

Filter: Basic Filter
Mode: Allow
Material: Gold

Mixed input

Gold

Wet SandResidue

Filter

Match → filtered route

Gold

Other → main route

Wet SandResidue

Filter Gold early while it is sitting near the bottom of the mixed pile.

Do not let Gold share the Kinetic Press input path.

Fix a Gold-clogged Kinetic Press →

How to filter Wet Seeds

Pull Wet Seeds out of a mixed seed stream, then send them to the Planter. This page does not replace the flower farm guide.

Wet Seed preset

Mixed input

Wet SeedSeed

Filter

Match → filtered route

Wet Seed

Other → main route

Seed

Open Flower Production →

Filter not working?

Pick the problem that matches what you see. Every result uses the same diagnosis: likely cause, check, fix, then show the rule in Builder.

Material takes the wrong route

Likely cause

Allow / Block may be reversed for what you are trying to do.

Check

Confirm the mode: Allow sends the selection down the filtered route; Block keeps it on the main route.
Confirm the selected material on the Filter.
Confirm you are editing a Basic Filter or an Advanced Filter, not the other one.

Fix

Open the Builder and flip Allow / Block until the preview matches the split you want.

Advanced Filter & routing edge cases

Why do Filters miss materials?

A correct rule can still miss materials when the mixed pile is deep. Lighter materials sitting on top may never reach the Filter reliably.

Deep mixed pile

Sand

GoldResidue

Wet Sand

Burnt Residue

Filter

Thin controlled stream

GoldResidue

Filter

Thin the input before adding more Filters.

Why does material get stuck inside a Filter?

If a pixel is allowed through, then changes type while it is still in the Filter, it may no longer be allowed to leave.

Sand

Water

Wet Sand

1. Keep material conversion away from the Filter opening.
2. Wet, heat or transform the material before sorting.
3. Or filter the transformed material instead.
4. Clear the already-stuck material manually before restarting.

Why is Florin leaking through an Advanced Filter?

Florin leaking?

This usually is not fixed by adding another random Filter. Check the rule first, then isolate the intakes if Florin still appears on the wrong route.

Check in order

01 Confirm the Advanced Filter rule includes Florin.
02 Check whether Dry Amethelis is displacing Florin upward.
03 Inspect adjacent openings and diagonal corners.
04 Isolate gas handling from the solid-material intake.
05 If needed, test a fully enclosed transfer setup with a small batch.

Florin leakage has also been reported when Dry Amethelis and Florin occupy opposite sides of the same Filter path. Isolate those intakes before assuming the rule is wrong.

Useful Filter layouts

Use the layout that matches the job. None of these is a best layout for every factory.

Single-material split

Best for: Gold / one material

Filter

Match → filtered route

Gold

Other → main route

SandResidue

Pull one selected material onto the filtered route and leave the rest on the main route.

Multi-material branch

Best for: Advanced Filter

Advanced Filter

Match → filtered route

Gold

Wet Sand

Other → main route

Residue

Several selected materials should share one filtered route, and everything else should continue.

Protected machine input

Best for: keeping unwanted material out of a machine

Filter

Kinetic Press

Block or divert the material that would clog the next machine before it reaches the input.

Sorting rule of thumb

Mixed pile? Filter the densest useful material first.

Common Filter questions

How do I use a Filter in Sandustry?+

A Filter splits two routes: materials that match the rule take the filtered route, and everything else continues on the main route. Start with Allow Gold if you need a first working split.

What is the difference between Allow and Block?+

Allow makes selected materials take the filtered route. Block keeps selected materials on the main route and lets the other materials take the filtered route.

How do I select multiple materials on an Advanced Filter?+

Place an Advanced Filter — it is a separate building — then add each material you want in the rule. A Basic Filter can only hold one solid material.

Why does my Filter miss some materials?+

Deep mixed piles, density layers and conversions near the opening can stop an otherwise correct rule. Thin the input and filter the densest useful material first.

Why does Wet Sand or Wet Seed get stuck in a Filter?+

Sand or Seed can pick up Water while passing the Filter and become Wet Sand or Wet Seed. If the new type is not allowed to leave, it can stay stuck in the opening.

Why is Florin getting through my Advanced Filter?+

First confirm Florin is in the rule and the mode is correct. Leakage has also been reported around Dry Amethelis / Florin setups even when the rule looks right — isolate those intakes instead of adding more Filters.

Quick answer

Basic Filter: One simple material rule
Advanced Filter: Multiple material rules

Need help?

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