
Select all faces in the UV Map (locate the cursor over the UV editor, then press A).In Unity 3D the first UV Map is used for the texture and the second UV Map is used for lightmap. Mesh tab: Select the UV Map to asign the texture to.Choose the object and switch to Edit Mode (TAB).Unity 3D will automatically assign them to the materials in the imported object.

When assigning textures in Blender ensure to select the files located in the Textures folder.

A subfolder named Materials will be automatically created by Unity.
