Getting Started

The shortest useful introduction to RedEngine is not an API tour. It is a small multiplayer session running in the Unity Editor. This path gets you there first; architecture and customization come after.

What you will have at the end

• RedEngine imported from the Unity Asset Store;
• the Compact Multiplayer Showcase imported;
• a valid Photon Fusion App Id and runner configuration;
• a server and at least one client running through Fusion Multi-Peer;
• a clear next step for building your own scene.

Allow about 20 minutes if Fusion is already installed.

1. Install the package

Follow Installing RedEngine. When Unity finishes compiling, open Tools > RedEngine > Welcome. The welcome window is a quick health check: it links to the settings asset, Fusion configuration, documentation, and samples.

2. Import the showcase

1. Open Window > Package Manager.
2. Select RedEngine Framework.
3. Open the Samples tab.
4. Import Compact Multiplayer Showcase.
5. Open the imported Content/Scenes folder.

The showcase is intentionally small enough to inspect. It is a better starting point than an empty scene because the important relationships—runner, game mode, controller, character, input, and UI—are already wired together.

3. Connect Fusion

Set the Photon App Id in Fusion's project configuration. The sample installer updates the single Assets/Resources/EngineSettings.asset, enables both showcase scenes in the active Build Profile, adds the sample assembly to Fusion Weaver, and selects Multi-Peer mode. Run RedEngine > Samples > Configure Compact Showcase to reapply those settings manually.

4. Run two peers

1. Right-click the Fusion ×1 play control and choose Start with 2 peer(s).
2. Use the neighboring Peer menu during Play Mode to choose which peer receives input.

You should be able to move both players, collect the weapon, fire, ride the moving platform, and see the same result from either peer. If only one peer responds, verify Peer Mode before debugging input.

5. Trace one action through the framework

Pick a simple action—jump is a good one—and follow it in the imported sample:

1. the Input Actions asset produces an input value;
2. InputSettings maps it to a fixed network input channel;
3. an InputContext routes the channel to gameplay code;
4. Fusion carries the input through the simulation tick;
5. a gameplay ability changes authoritative state;
6. presentation code reacts to the replicated result.

That path is the framework in miniature. Keep simulation state in the Fusion path; reserve ordinary Unity timing and callbacks for presentation work.

Where to go next

• Building your own scene: Your first multiplayer scene
• Understanding the moving parts: Framework overview
• Choosing a gameplay system: Features
• Understanding shared services: start from Subsystems
• Looking up a gameplay feature: start from Features

A quick troubleshooting pass

Symptom	First thing to check
Unity cannot resolve RedEngine assemblies	Package path and required dependencies
Play Mode quits during startup	Assets/Resources/EngineSettings.asset exists and has a runner
Scene travel fails	Scene is in the active Build Profile and assigned in EngineSettings
Multi-Peer refuses to start	Fusion Peer Mode is Multiple
Fusion reports InvalidAuthentication	Set a valid Fusion App Id in PhotonAppSettings
A player does not receive input	The correct player is selected in the Peer toolbar menu
A network actor is missing	Its prefab has NetworkObject and is registered with Fusion