Physics Examples

This repository contains test projects, examples, and a test package for Unity's 2D physics, spanning two API generations:

• PhysicsCore2D — examples for the newer 2D physics core API (Unity.U2D.Physics), located at the repository root:
  • Sandbox Project — interactive playground scenes
  • Primer Project — focused single-concept examples
  • Snippets Project — minimal API usage demos
• OldPhysics2D — examples that use the older "Physics2D" component API.

Packages/com.unity.2d.physics.extras is a shared local package referenced by the PhysicsCore2D projects.

.claude/ contains skills you can copy into your own .claude folder to better work with PhysicsCore2D.

• Dev Videos

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Acknowledgement and thanks to Erin Catto (the creator of Box2D v3), upon which significant portions of the "Sandbox" project are based.

https://github.com/erincatto/box2d

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Branch Names

Each branch represents a specific version of Unity. As features are added in a public release, those features should be represented in that branch and future Unity version branches i.e. branch names such as "2022", "6000.3" (etc) exist.

• master represents the current latest release of Unity, updated only when new final releases have been public for a while.
• unsupported/xxx represents versions that are currently in alpha/beta release state.

Archived Versions

Older Unity version branches are not kept as live branches. They are archived as annotated tags named archive/<version> (for example archive/2019, archive/6000.1). A tag preserves the exact final state of that version permanently while keeping the branch list focused on supported versions.

To archive a branch, tag its tip, push the tag, then delete the branch:

git tag -a archive/2019 origin/2019 -m "Archive 2019 branch"
git push origin archive/2019
git push origin --delete 2019

To restore an archived version into a working branch:

git branch 2019 archive/2019

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Unity Discussions: https://forum.unity.com/members/melvmay.287484/