Memory Management in UEFN

Efficient memory management is critical in Unreal Editor for Fortnite (UEFN) to ensure that your creations run smoothly and remain within performance limits. UEFN utilizes advanced tools like memory budgeting and streaming to balance the resources used by the island’s assets. For creators, understanding these tools and implementing best practices is essential to keep your project on budget while delivering a polished experience.

UEFN provides detailed insights into memory usage. After running a memory calculation, you can access a detailed breakdown of the top 100 memory-heavy assets on your island by navigating to Window > Message Log > Memory Test Results. This allows you to pinpoint resource-intensive assets and make informed adjustments. Creators can also use the Project Size window to identify memory-heavy objects on disk, as these are often runtime memory hogs. Reducing their quality or replacing them with optimized alternatives can significantly cut down memory usage.

Techniques for Optimizing Memory

1. Streaming and Content Distribution: For large or densely packed islands, enabling Streaming in the World Partition panel allows portions of your map to load dynamically, reducing runtime memory usage. Even on smaller islands, a well-planned streaming strategy can help by unloading unnecessary assets outside the player's view. Distributing content evenly across the map also facilitates effective streaming, as dense areas may prevent assets from being efficiently offloaded.

2. Reusing and Reducing Assets: Reusing assets is another vital strategy. For example, instead of creating 100 unique trees, use 5 variations and duplicate them around your map. This minimizes the impact on memory. Similarly, lowering the complexity of custom meshes by adjusting their Keep Triangle Percent in the Nanite settings reduces their memory footprint while maintaining visual fidelity.

What to Do When Your Project Is Over Memory Budget

If your project exceeds the memory budget, try the following steps to optimize it:

• Check Memory Test Results: Review the top memory-heavy assets in Window > Message Log > Memory Test Results and optimize or replace them.
• Enable Streaming: Turn on Streaming in the World Partition panel to load only relevant parts of your island at runtime.
• Reduce Devices: Minimize the number of unique devices used and favor reusing instances of the same device.
• Simplify Custom Meshes: Lower the quality of custom assets by adjusting their triangle counts or using simplified LODs.
• Distribute Content Evenly: Spread actors and props across the island to optimize memory usage and enhance streaming efficiency.
• Use Data Layers: Subdivide your map into layers for areas not intended to be visible simultaneously.

Managing Devices and Configurations

Devices often represent significant memory costs in UEFN. To optimize, limit the number of unique devices and instead use instances of the same device, which incurs a much smaller memory cost. Additionally, generating hierarchical level of details (HLODs) throughout the project lifecycle ensures that only visible objects from a distance contribute to memory usage.

3. Leveraging Data Layers: If your island includes distinct areas like an underground dungeon, use Data Layers to manage configurations displayed at runtime. This isolates parts of your map to be loaded only when needed, reducing unnecessary memory allocation.

Efficient Memory Management is Key

Efficient memory management in UEFN is a blend of planning, optimization, and leveraging available tools. From utilizing memory reports to implementing strategies like streaming and asset reuse, creators can maintain high-quality islands without exceeding memory budgets. Regular testing and iterating on these principles ensure that your creations are both visually compelling and performance-friendly.

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