Improving the MegaAssemblies Workflow

General / 11 August 2022

Prefabs are an incredibly common, extremely powerful tool in any world-builder's kit. If you want to place a campfire, you can combine a firepit, VFX, lights, and sound effects into one asset to be placed and updated together. However, Unreal Engine 5 doesn’t have a true prefab system. I know myself and many others were ecstatic when Epic first teased the Packed Level Instance Blueprints (aka MegaAssemblies) system for Unreal 5. When I first got my hands on the early access version of UE5 I found building out MegaAssemblies to be a tedious, confusing process, even after doing it a few times. To make matters worse, the system only supports static meshes. This means a major feature of traditional prefabs – the ability to package multiple asset types together – remains missing. 

In an effort to implement a pseudo-prefab system in UE5, I spent countless hours digging through docs, attempting to build them manually through various combinations of features. I landed on a happy marriage between Packed Level Instance Blueprints, Level Instances, and the default in-level editing features in UE5. This results in a more modern feel to building out “prefabs” that is as simple as selecting your assets and using the right-click context menu.

For more information on the creation of this tool, please see my longer post here.

Quick example of building a prefab from various assets, inside a level in real time.

Examples of editing the prefab, as well as the Packed Level Instance Blueprint/MegaAssembly within the prefab.