Why Remote procedure calls in Unity? - Purpose & Use Cases

The Big Idea

What if you could make your game's remote players act instantly with just a simple function call?

The Scenario

Imagine you are building a multiplayer game in Unity where players interact in real time. Without remote procedure calls, you would have to manually send and receive messages for every action, like moving a character or shooting, and then write extra code to interpret those messages on each player's device.

The Problem

This manual messaging is slow and complicated. It's easy to make mistakes, like sending wrong data or missing updates. Debugging becomes a nightmare because you have to track many small messages and their timing. The game feels laggy or buggy, frustrating players.

The Solution

Remote procedure calls (RPCs) let you call functions on other players' devices as if they were local. You write simple code like calling a method, and Unity handles sending the message and running the code remotely. This makes your multiplayer code clean, fast, and easier to manage.

Before vs After

✗ Before

SendMessageToAllPlayers("Move", x, y, z);
// Then parse and apply movement on each client

✓ After

[ClientRpc]
void RpcMove(Vector3 position) {
  transform.position = position;
}

What It Enables

RPCs enable smooth, real-time multiplayer interactions by making remote actions feel local and automatic.

Real Life Example

In a Unity racing game, when one player presses the accelerate button, an RPC updates all other players' cars instantly to show the speed change without delay or confusion.

Key Takeaways

Manual message handling is slow and error-prone for multiplayer games.

RPCs let you call functions remotely as if they were local.

This makes multiplayer code simpler, faster, and more reliable.