Texturing & materials · Beginner

Opacity map

A grayscale texture that sets how see-through each part of a surface is

Also called Alpha map, Transparency map

What is an opacity map?

An opacity map, also called an alpha map or transparency map, is a grayscale texture that sets how see-through each part of a surface is. White is solid, black is invisible and gray is partly clear. It lets a flat card look like a leaf, a fence or a strand of hair.

Think of it like this

It is like a paper doily on a table: the holes let the table show through, while the paper parts stay solid.

Where it fits in a 3D project

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

Surface: Giving the shape its color and material: UVs, textures and shaders.

Base colorNormalRoughnessMetallicOpacityMaterial
The opacity map is one of several texture maps a material combines.

How an opacity map works

  1. 01Paint white where the surface should be solid and black where it should vanish.
  2. 02The material reads the map, as its own image or from a texture’s alpha channel.
  3. 03The renderer cuts out or blends the surface based on each pixel’s value.

Opacity map vs alpha channel

PropertyOpacity mapAlpha channel
What it isA map used for transparencyA fourth channel inside an image
Stored asIts own image or a channelPart of a PNG or similar file
Used forTransparency onlyTransparency, masks or packed data

An alpha channel is a place to store data and an opacity map is a job; the opacity map often lives inside that alpha channel.

Where an opacity map is used

  • Leaves, grass and hair cards in games
  • Chain-link fences and lace without modeling every hole
  • Fading glass, smoke and decals

Beginner tip

For hard edges like leaves, use cutout transparency rather than blending. It is cheaper, sorts correctly and stops objects showing through each other in the wrong order.

Terms related to an opacity map

Opacity map FAQ

What is alpha blend vs alpha clip?
Alpha clip, or cutout, makes each pixel fully solid or fully invisible, which is fast and suits leaves. Alpha blend allows partial transparency for glass or smoke, but costs more and can draw in the wrong order.
Is an opacity map the same as an alpha map?
Yes. They are two names for the same idea. Some tools also call it a transparency map or a cutout mask.
Why do transparent objects look wrong in my game?
Usually it is sorting. Blended transparent surfaces must be drawn back to front, and overlapping ones can swap order. Switching to alpha clip where you can fixes most cases.

Updated October 29, 2026 · Browse all 3D terms