It is fundamental to have high-quality reflections while carefully balancing the available runtime resources. Cubemaps are a technique that let you do this.
Reflections are an important part of the visual world and therefore provide better immersion and credibility for your environment.
Generating reflections in real time is very computationally expensive. Precomputed reflections enable you to reduce the load at runtime, while their quality can be controlled by adjusting the resolution.
A cubemap is a 360-degree snapshot of the world that is taken from a specific spot, looking along each orthogonal axis. If you generate a cubemap looking from a reflective object, you can get the reflected color just by sampling the cubemap along the appropriate direction.
Unreal Engine has an existing native implementation of precomputed reflections with sphere reflection captures, however cubemaps produce higher resolution, and therefore better results.
This section contains the following subsections: