Virtual Texturing | Unreal Engine 4.27 Documentation

Virtual Texture support for your project enables you to create and use large-sized textures for a lower—and more consistent—memory footprint at runtime.

Virtual Texturing Methods

Unreal Engine supports two virtual texturing methods: Runtime Virtual Texturing (RVT) and Streaming Virtual Texturing (SVT).

Runtime Virtual Textures	Streaming Virtual Textures
Supports larger texture resolutions. Texel data cached in memory on demand. Texel data generated by the GPU at runtime. Well suited for texture data that can be rendered on demand, such as procedural textures or composited layered materials.	Supports larger texture resolutions. Texel data cached in memory on demand. Texel data cooked and loaded from disk. Well suited for texture data that takes time to generate, such as lightmaps or large, detailed artist created textures.

Runtime Virtual Texturing

RVT supplies an efficient way to render complex, procedurally generated, or layered materials. This makes RVT ideal for rendering complex materials for Landscapes. It enables improved rendering performance and workflows for Landscape Splines, decals for meshes and materials, along with general Landscape and object blending.

For additional information, see Runtime Virtual Textures.

Streaming Virtual Texturing

Streaming Virtual Texturing reduces texture memory overhead when using larger texture sizes, including support for virtual texture lightmaps and UDIM (U-Dimension). Streaming virtual textures is an alternative way to stream textures from disk compared to existing mip-based texture streaming.

For additional information, see Streaming Virtual Textures.

Virtual Texture Lightmaps

Enabling support for virtual texture lightmaps can improve streaming performance and quality of lightmap bakes.

Enable virtual texture support for lightmaps from the Project Settings by going to Engine > Rendering and setting Enable virtual texture lightmaps.

Enable the following console variables to control how virtual texture lightmaps are used in your project:

Console Variable	Description
`r.IncludeNonVirtualTexturedLightmaps`	Controls whether non-VT lightmaps are generated/saved. Including non-VT lightmaps will constrain the atlas size, which removes some of the benefit of VT lightmaps.
`r.VT.EnableLossyCompressLightmaps`	Enables lossy compression of virtual texture lightmaps. Lossy compression has lower quality on lightmap textures compared to regular color textures.