Using Cubemaps

This document goes over how to utilize Cubemaps once you have imported them into Unreal Engine 4 (UE4).

Using Cubemaps

There are multiple ways to apply Cubemaps in UE4. Two popular uses are via Ambient Cubemaps and Cubemaps within Materials.

Ambient Cubemaps

The Ambient Cubemap is only intended to be used for a subtle directional ambient term (useful in games with completely dynamic lighting), or for model viewer applications.

Because light comes from many directions, we cannot simply use shadow maps for this light type. SSAO is applied to get contact shadows from nearby geometry (see Ambient Occlusion ).

The show flag "Lighting Image Based Lighting" can be used to toggle the rendering of Ambient Cubemaps.

Ambient Cubemap AmbientCubemapTexture.png

In this image, a Cubemap image has been automatically laid out into a "Longlat" format.

Property

Description

Cubemap Texture

The Cubemap used for ambient lighting. The texture should be created by importing a .HDR image in the Longitude/Latitude sphere unwrapping format. UE4 automatically precomputes blurry versions of the texture and stores the result in one Cubemap Texture. The lower resolution Mips of the texture store the diffuse pre convolved version of the HDR environment.

Intensity

A scaling factor for the brightness of the effect. Possible uses: brightness tweak existing Cubemaps.

Tint

A filter color to apply to the Cubemaps. Possible uses: colorize existing Cubemaps, animate a sky color change.

The Cubemap in this image is derived from a light probe by Paul Debevec. http://gl.ict.usc.edu/Data/HighResProbes/