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Ue5 Stop Actor From Destroyinf When Low

8 min read Oct 13, 2024
Ue5 Stop Actor From Destroyinf When Low

How to Prevent Actors from Being Destroyed When Low on Memory in UE5

In Unreal Engine 5 (UE5), the engine's memory management system often automatically destroys actors to free up memory when resources become scarce. This can be problematic if you have critical actors in your game world that need to persist even under memory pressure. This article will explore how you can prevent actors from being destroyed when the engine encounters memory constraints.

Understanding the Problem:

UE5's memory management system is designed to ensure optimal performance. When the engine detects low memory conditions, it will attempt to reclaim resources by destroying less important actors. This is typically a desirable behavior, but it can disrupt your game's flow if essential actors are destroyed unexpectedly.

Key Causes of Actor Destruction:

  1. Low Memory: The most common reason for actor destruction is a shortage of available memory. This can occur due to various factors, such as large levels, complex assets, or a high number of active actors.
  2. Garbage Collection: UE5's garbage collection system periodically identifies and removes unused objects in memory. If an actor is no longer referenced by any other object, it may be marked for destruction.
  3. Level Streaming: If you're utilizing level streaming, actors in unloaded levels may be destroyed to free up memory.

Solutions to Prevent Actor Destruction:

Here are several strategies you can employ to prevent your vital actors from being destroyed when memory is low:

1. Set the bAlwaysRelevant Property:

  • What it does: This property tells the engine that the actor is always considered "relevant" and shouldn't be destroyed under normal memory pressure.
  • Where to find it: In the Details panel of your actor in the editor, you'll find the bAlwaysRelevant checkbox within the Actor category.
  • Example: If you have a player character, setting bAlwaysRelevant to true will ensure it remains in the game even when memory is tight.

2. Use the bNetRelevant Property:

  • What it does: This property is relevant for multiplayer games. Actors marked as bNetRelevant are considered important for network replication and are less likely to be destroyed.
  • Where to find it: In the Details panel of your actor, under the Replication category.
  • Example: For important gameplay elements that need to be replicated across clients, setting bNetRelevant to true can increase their resilience.

3. Increase the Priority of Your Actor:

  • What it does: The Priority property determines the actor's importance in the engine's memory management system. Actors with a higher priority are less likely to be destroyed.
  • Where to find it: In the Details panel of your actor, under the Actor category.
  • Example: You can increase the priority of essential gameplay actors to prevent them from being sacrificed during low memory situations.

4. Implement a Custom Memory Management Strategy:

  • What it does: This involves developing your own logic to manage memory more effectively. You can introduce custom systems for pooling objects, pre-loading assets, and selectively destroying less critical actors.
  • Example: You might create a system that automatically disables or hides distant objects when memory is low, reducing the overall memory footprint.

5. Optimize Your Game for Memory Efficiency:

  • What it does: Analyzing your game's memory usage can reveal areas for optimization.
  • Examples:
    • Use lower-resolution textures when appropriate.
    • Utilize the FMemory::Malloc function to allocate memory more efficiently.
    • Leverage streaming techniques to load content on demand.

6. Consider the Always Loaded Option for Levels:

  • What it does: This option prevents a level from being unloaded, ensuring its actors remain persistent.
  • Where to find it: In the Level Settings window for your level.
  • Example: If you have a crucial level that should always be active, setting Always Loaded to true can prevent its actors from being destroyed.

7. Use the UObject::ForceGarbageCollection Function:

  • What it does: This function forces the garbage collector to run immediately, potentially freeing up memory for your essential actors.
  • Example: You can trigger garbage collection before a memory-intensive operation to ensure enough memory is available.

8. Utilize the GCSettings Class:

  • What it does: The GCSettings class provides methods for configuring the garbage collector's behavior, allowing you to adjust the frequency of garbage collection.
  • Example: You can increase the delay between garbage collection cycles if you anticipate memory pressure.

Important Considerations:

  • Performance: Implementing these strategies might affect your game's performance, so carefully test and profile your game after making changes.
  • Game Design: Consider the impact on your game's design. Destruction of actors can sometimes be used as a gameplay mechanic.
  • Balance: Strive for a balance between memory efficiency and gameplay experience.

Conclusion:

Preventing actors from being destroyed when memory is low requires a multifaceted approach. By understanding the engine's memory management system, utilizing the available properties, and optimizing your game, you can ensure that critical actors remain persistent even in challenging memory conditions. Always test and profile your game to ensure your chosen solutions are effective and maintain the desired performance levels.

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