# generateLightMapVertexColorsWithLights(toConsider:objectsToConsider:vertexAttributeNamed:) Calculates static lighting information for the mesh and saves it in the mesh as a vertex color attribute. ``` func generateLightMapVertexColorsWithLights(toConsider lightsToConsider: [MDLLight], objectsToConsider: [MDLObject], vertexAttributeNamed vertexAttributeName: String) -> Bool ``` ## Parameters `lightsToConsider` An array of lights that should affect the mesh. `objectsToConsider` An array of other objects in the scene that should affect static lighting for the mesh. `vertexAttributeName` The name of the vertex attribute for storing generated vertex color data. ## Return Value if light map generation succeeded; otherwise . ## Discussion A light map contains, for each point on a surface, information about how light sources in a scene affect the shading of that surface. Because many of the lighting effects in a scene are static—that is, the positions of lights relative to the surfaces they illuminate do not change over time—you can achieve high-fidelity lighting effects with little render-time performance cost by using this method to precalculate (or “bake”) light information into a mesh. You can then use the resulting information in shading to produce a more realistic render. This method saves light map data as per-vertex colors. Using vertex colors to modulate shading can result in similar results without the texture memory and vertex attribute overhead of a texture map, but the fidelity of this effect depends on the vertex complexity of the mesh. Vertex colors are saved in the vertex attribute specified in the `vertexAttributeName` parameter. If the mesh already contains that attribute, this method overwrites the contents of the corresponding vertex buffer. If the mesh does not contain that attribute, this method creates a new attribute and updates the mesh’s [`vertexDescriptor`](/documentation/ModelIO/MDLMesh/vertexDescriptor) object accordingly. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)