Lighting & rendering · Intermediate

Lightmap

A texture of baked lighting that lets real-time scenes look richly lit

Also called baked lighting

What is a lightmap?

A lightmap is a texture that stores precalculated lighting for the surfaces in a scene, including soft shadows and bounced light. It is baked once ahead of time, then laid over the surfaces at runtime, so games and real-time viewers show rich lighting without calculating it every frame.

Think of it like this

It is like painting shadows and sunlight straight onto a theater set: it looks lit from every seat, but the lights cannot move during the show.

Where it fits in a 3D project

  1. Create
  2. Surface
  3. Rig
  4. Animate
  5. Render
  6. Export

Render: Lighting the scene and turning it into images or video.

How a lightmap works

  1. 01Each object gets a second UV layout with no overlapping pieces.
  2. 02A renderer calculates lighting for the static scene and bakes it into textures.
  3. 03The engine blends those textures with the surfaces’ own materials at runtime.
  4. 04Moving objects use separate real-time lighting, since the bake cannot change.

Lightmap vs real-time lighting

PropertyLightmapReal-time lighting
CalculatedOnce, before runningEvery frame
QualitySoft shadows and bounced lightDepends on engine and budget
Changes while runningNoYes
Cost while runningVery lowHigher

Bake lightmaps for static scenes where lights never move, and use real-time lighting for anything that changes, like a day-night cycle or a flashlight.

Where a lightmap is used

  • Static levels in games
  • Architectural walkthroughs and VR
  • Mobile and web scenes on modest hardware

Beginner tip

Leave generous spacing between islands in lightmap UVs. Pieces packed too tightly bleed light into each other, causing dark seams and glowing edges.

Terms related to a lightmap

Lightmap FAQ

What is a lightmap UV?
A second UV layout used only for lighting. Unlike a texture UV, every surface needs its own space with no overlaps, so each spot can store its own light.
Why is my lightmap blotchy?
Usually the lightmap resolution is too low or the bake used too few samples. Raise the texel density on important surfaces, increase bake quality, and check the lightmap UVs for stretching.
Can lightmaps handle moving lights?
No. A lightmap is a fixed snapshot of light. Engines pair it with real-time lights, and with light probes that store light for moving objects, to cover what changes.

Updated October 29, 2026 · Browse all 3D terms