Texture Baking in Blender Cycles: A Guide to UV, AO, and Normal Maps

What will you learn in this guide?

Texture baking transfers selected information from Cycles’ material and lighting calculations to an image texture or Color Attribute layer. This guide covers the mesh, UV, and target setup required for baking; choosing a suitable bake type; matching space settings for normal maps; and troubleshooting seams or projection issues in the result.

The Blender Manual lists basic color and normal maps for game engines, AO or procedural textures, and lightmaps prepared to provide global illumination or reduce render times in games among the main uses for baking. In architectural visualization, this approach can be used to transfer specific surface or lighting information to textures for scene assets that are reused.

Requirements: mesh, UV, and bake target

The object to be baked must be a mesh and must have a UV map. The output can be sent to the image in the active Image Texture node or to the active Color Attribute layer. If you are using an image, the Image Texture node in the relevant material must be both active and selected. A material that does not meet these conditions will not bake to an image. For a Color Attribute target, the active object must be a mesh.

The sources include Blender Manual documentation for versions 2.80, 2.93, and 4.5, as well as the current manual page. These are version details for the documentation; they do not indicate a Blender version required for baking. The sources do not specify system requirements either. Before you start, check that Cycles baking options are available in your Blender installation and that the selected target type is suitable for the scene.

Cycles uses render settings during baking; the manual gives sampling and light bounce values as examples. This means bake quality is not independent of the scene’s render settings. Before you begin, select the correct object, review its UV map, and prepare the target you will use for the output.

Baking in Blender: step by step

1. Check the mesh and UV map. The surfaces to be baked need UV coordinates. The UV map defines how points on the mesh correspond to locations in the texture. Check the resulting image after baking to assess any visible seams.

2. Set the bake target. To output to an image, select and activate an Image Texture node in the material; the image to be baked must be associated with that node. Alternatively, use the mesh’s active Color Attribute layer. Before baking, make sure the target and the object being baked are correct.

3. Choose a bake type for your intended use. The type in the Bake panel determines which surface information is transferred to the output:

   • Combined combines materials, textures, and lighting, but does not include specular contribution. You can separately choose which contributions to include in the result.

   • Ambient Occlusion bakes AO information and does not take scene lights into account.

   • Shadow transfers shadow and lighting information; Normal transfers surface normals to an RGB image.

   • Diffuse, Glossy, Transmission, Roughness, and Emit can be used to bake the corresponding material passes.

   • UV displays the UV coordinates used for the mesh’s texture mapping in the image channels.

   The manual also includes the Bake from Multires option for creating normal or displacement maps from a high-detail mesh. This method bakes the difference between the low- and high-resolution levels of a Multiresolution Modifier.

4. Match normal map settings. Normal baking can use Object or Tangent space. The Blender Manual describes Tangent space as the default and suitable option in most cases. For correct results, the space used for baking must match the Normal Map space setting in the material’s Image Texture settings. Choosing different settings in the two places can prevent the normal information from being used as expected.

5. Transfer detail with Selected to Active. This method bakes surface information from selected objects onto the active object; rays are cast from the low-poly object toward the high-poly object. If the rays have trouble finding their target, consider the Max Ray Distance or cage options. A cage controls the volume in which rays are cast. When using a manually prepared Cage Object, its topology—that is, its face count and face order—must match the base mesh. Also be aware that omitting a cage can result in marks or distortion along the edges.

6. Set a margin and run the bake. When baking to an image, a margin adds pixels around UV islands to help reduce interruptions at seams. Extend extends edge pixels outward; Adjacent Faces uses pixels from neighboring faces across UV seams. The margin size is specified in pixels. If needed, use the option to clear the image before baking; then run the bake and inspect the output.

Common issues and checklist

• If the result is blank: Check that the mesh has a UV map and that the correct bake target is selected. For an image target, the Image Texture node must be both active and selected; making the node active alone is not enough.

• If UV seams are visible: Review the margin type and pixel size. The margin fills around UV islands to help reduce interruptions that can occur during texture filtering and mipmapping.

• If the normal map does not look as expected: Compare the normal space in the bake settings with the Normal Map setting in the material. Bear in mind that hard-edge splits, such as applied Edge Split splits, can cause non-smooth normals along edges.

• If marks appear in a Selected to Active bake: Reassess the ray distance and whether to use a cage. If you prepared a custom cage, verify that its topology matches the base mesh.

• If you run into memory issues: According to the manual, each object used as a bake source creates a fixed memory overhead in CPU memory. Consider joining high-poly objects to help prevent crashes caused by insufficient memory. Test whether this is suitable for your scene before doing so.

What changes in an architecture and archviz workflow?

Architecture firms and visualization teams can try baking to transfer surface information to textures for reusable scene objects or to prepare lightmaps for game engines. The Blender Manual notes that baking AO for main objects can save render time by letting you disable AO during a full render. This does not mean the method will produce the same result in every scene; UV preparation, target selection, and scene settings all affect the outcome.

The manual does not specify system requirements, but it does state that bake source objects use a fixed amount of CPU memory. For this reason, monitor memory use with test bakes, especially in high-poly scenes. The sources provide no information about licensing costs or compatibility with other applications. Before adding baking to a production pipeline, verify the result in the target application and check how it fits with the team’s texture workflow.

Next steps

Start with a small test using a single piece of furniture, a section of façade, or another scene object. Once the UV map and bake target are working correctly, inspect AO, normal, and, if needed, Combined results separately. For transfers from a high-detail model to a low-detail target, test ray distance and cage settings in a controlled way. Finally, check that the bake output looks as expected in its intended use.

Sources and licensing

This guide is an English adaptation of information on the Blender Manual’s “Render Baking” page. The references used are the current Blender Manual page and the 2.80, 2.93, and 4.5 documentation. The sources are published under the CC BY-SA 4.0 license.