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Collider Composition

Compose Unity 2D physics colliders CompositeCollider2D merge, multiple PolygonCollider2D…

Stops the collider explosion that drags Unity 2D physics to a crawl. It composes scattered box and polygon colliders under a single CompositeCollider2D, separates trigger from solid via a physics layer matrix, and tunes the physics step so a level packed with hundreds of tiles still holds frame rate on low-end mobile.

$15 one-time
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Prices include 20% VAT. · Forged on real agency work · one-time, no lock-in

  • Type Skill
  • Category Game Dev
  • Delivery Email · instant
  • License One-time
Run preview
forgehouse, collider-composition

Inside the run · no black box

See the actual work before you buy it.

Profiler first, opinions later: 500 tile colliders showing 8-12ms of physics time is the baseline to beat. Merging, layer matrix pruning and per-platform step tuning bring it under 1ms on mobile.

  1. Measures first: opens the Profiler and reads Physics2D.Simulate time and total collider count. A tilemap with 500 individual tile colliders typically shows an 8-12ms physics step, which is the baseline to beat.
  2. Merges colliders under a CompositeCollider2D parent: TilemapCollider2D and PolygonCollider2D children get UsedByComposite set true (an AssetPostprocessor auto-fixes any that are missed), the parent Rigidbody2D is forced Static, and geometry type Outlines turns 800 tile colliders into roughly 40 merged edge chains.
  3. Separates trigger from solid: a wall or NPC body is a solid collider on the Solid layer, while interaction radius is a second collider on its own Interaction layer with IsTrigger true. Toggling IsTrigger on a single shared collider is the bug that lets players walk through walls.
  4. Rewrites the Layer Collision Matrix deny-by-default: out of 256 possible layer pairs only the roughly 22 that matter stay enabled (Player vs Solid, Projectile vs Enemy...), which cuts broad-phase checks by about 35 percent.
  5. Tunes the physics step budget per platform: mobile gets a 20Hz fixed timestep with reduced velocity and position iterations, fast projectiles get Continuous collision detection so they stop tunneling through walls.
  6. Handles dynamic geometry last: every door open or close disables the child collider, calls GenerateGeometry on the composite, and invalidates the pathfinding grid, then the checklist verifies Physics2D.Simulate lands under 1ms on mobile.
Use cases · what happens when you plug it in

One power source. 6 lines out.

collider-composition · core

core active · 6 lines

  1. Merge hundreds of tile colliders into one composite outline

    ✓ merge hundreds of tile c…
  2. Separate NPC interaction triggers from solid bodies

    ✓ separate npc interaction
  3. Configure a deny-by-default physics layer collision matrix

    ✓ configure a deny-by-defa…
  4. Stop fast projectiles tunneling through walls

    ✓ stop fast projectiles tu…
  5. Regenerate composite geometry for dynamic doors

    ✓ regenerate composite geo…
  6. Cut physics step time when the Profiler shows a bottleneck

    ✓ cut physics step time when
Benefits · what you walk away with

Yours to keep.

Drag time forward. Watch what stays.

Forever

That's what owning means.

The rented stack

ai writing tool: subscription

expired · access lost

analytics suite: subscription

expired · access lost

design platform: subscription

expired · access lost

(nothing left)

Your forge

  1. Collapse hundreds of tile colliders into a handful of merged outlines

    license: perpetual
  2. Hold mobile frame rate by tuning the fixed timestep and iteration counts

    license: perpetual
  3. Skip irrelevant collision pairs so the broad phase does far less work

    license: perpetual
  4. Eliminate the 'character stuck in wall' and ghost-through-wall bugs that tank reviews

    license: perpetual

subscriptions expire · deeds don't

What's included · the full manifest

Everything in the box.

Pick a piece up. Watch it work.

Canonical CompositeCollider2D prefab structure and auto-configure Reset() script

part 01 of 06 · in the box

6 parts · one working system · ships instantly by email

Who it's for

This wasn't forged for everyone.

  • Not for you if you'd rather rent a tool than own one.
  • Not for you if you want someone else to run your stack.
  • Not for you if you're happy guessing.
Still here? Good.

For Unity 2D/2.5D game developers whose tilemap-heavy scenes are choking on collider count and physics step time, especially when targeting low-end mobile.

then this was forged for you.

Works with

Universal by design: these run in any AI. Delivered in the open Agent Skills + MCP format (native in Claude); ChatGPT, Gemini, Cursor and Copilot adapt the same files their own way.

  • Claude Native format
  • ChatGPT Adapts via open standards
  • Gemini Adapts via open standards
  • Cursor Adapts via open standards
  • Copilot Adapts via open standards
Questions · still in the air

Catch what's on your mind.

the air is clear. nothing between you and the forge.
catch a spark: the forge will answer

  1. Does this fit a Tilemap-based scene, or only hand-placed colliders?

    It is aimed squarely at tilemap-heavy 2D and 2.5D scenes, merging the scattered tile colliders into one CompositeCollider2D outline. That is exactly the case where collider count drags the physics step down.

  2. If I merge hundreds of colliders into one, does collision behave differently?

    The composite keeps the same solid outline, so what blocks the player still blocks the player. Triggers are split onto their own physics layers, so an NPC interaction zone stays separate from a solid wall rather than getting merged into it.

  3. Will this fix my frame rate if colliders are not the real bottleneck?

    No, it targets collider count and physics step time specifically. If your drop comes from draw calls, scripts or garbage collection, the gain here will be small and the fix belongs in that system instead.

  4. How is it delivered?

    By email right after purchase: ready to run, downloaded instantly, no setup wait.

  5. One-time or subscription?

    A one-time purchase; no subscription or hidden fees. VAT (20%) is included.

  6. Can I get a refund?

    As a digital product, it can’t be refunded once downloaded. That’s why we show exactly what’s inside and who it’s for, right here.