I’ve been diving into Unreal Engine’s networking and replication, and I’ve got a bit of a dilemma that I’m hoping you all can help me with. I’m getting a handle on RPC (Remote Procedure Calls) and replication and trying to figure out what the best practices are for handling minor changes in my game.
So, here’s the scoop: I often rely on RPCs for even the simplest tweaks, like altering character collision based on whether they’re hiding or not. For instance, I had a scenario where I wanted to change a character’s collision from blocking to overlapping when they entered a hiding spot. Initially, I was just calling this function on the server, but it didn’t sync up properly with the listen server, and my clients ended up flickering back and forth without being able to interact with the environment. Once I switched to a multicast, everything smoothed out.
However, now I’m starting to wonder if I’m leaning too heavily on RPCs for these little adjustments. I mean, it seems more practical to handle these changes via RPC since they’re environment-dependent, but I worry about performance and network traffic. Should I be using replicated variables more often for these small changes instead? At what point does RPC use become detrimental to performance? I know not to go overboard with RPCs, but finding that balance between convenience and efficiency is tricky.
I’d love to hear your experiences. Have any of you dealt with similar challenges? What’s your take on using RPCs versus replicated variables for minor tweaks? Are there certain types of changes you’d always advocate for using variables instead? Any guidance on managing this would be super helpful!
Using RPCs vs. Replicated Variables in Unreal Engine
It sounds like you’re really getting into the nitty-gritty of networking in Unreal Engine! It’s super common to get a bit tangled in how to best handle replication and RPCs, especially when you’re trying to synchronize minor changes across clients.
From what you described, using a multicast to update all clients at once was a solid move for preventing that flickering when changing collision settings. Multicasts are great when you want to ensure that all players see the same state at the same time.
However, relying too heavily on RPCs can lead to a few issues. For minor tweaks, like character collision changes, it might be more efficient to use replicated variables. This way, the engine takes care of syncing those changes automatically instead of sending out specific calls every time. For example, if the collision type changes based on gameplay state (like hiding), you can just update a replicated variable, and it’ll handle the rest.
As a rule of thumb, RPCs are better for actions that need to be executed immediately and require precise control over when they happen (like firing a weapon or triggering a game event). Replicated variables, on the other hand, are often better for state changes that can be updated less frequently or are not as critical for immediate response.
Ultimately, balance is key. If you find yourself using RPCs for things that don’t need immediate attention or are minor changes, it might be time to consider switching to variable replication. Just keep an eye on your performance metrics, and don’t hesitate to test different approaches to see what works best for your specific situation.
Good luck, and keep experimenting! Networking can be tricky, but it sounds like you’re on the right path.
In scenarios like adjusting character collision states—such as switching from blocking to overlapping when entering cover—it’s generally best practice to employ replicated variables rather than frequent RPC calls, especially if the changes are state-driven and persistent. Using a replicated variable ensures synchronization across clients with a lower overhead, as Unreal Engine efficiently handles state replication. You can still leverage Unreal’s built-in replication conditionals or the “ReplicatedUsing” mechanism to manage side effects like collision updates immediately when the variable changes, ensuring smooth transitions without the potential overhead and reliability issues of multicast RPCs.
RPCs, especially multicast RPCs, can quickly escalate bandwidth usage and network overhead if used excessively, particularly when dealing with rapid, incremental changes. While multicast RPCs might be convenient for immediate, one-off events, persistent or frequently toggling states are better handled through replication. Typically, RPCs shine in situations involving discrete actions or events that occur infrequently—for instance, triggering a single visual effect or initiating an environmental interaction. By transitioning to replicated variables for continuous state-driven changes, you maintain clarity, efficiency, and a more predictable network performance.