MTL files reference materials used by OBJ 3D model files. MTL files are saved as plain text so you can open and edit them in any text editor like Notepad or TextEdit.
Each material in an MTL file starts with “newmtl” followed by statements describing the material color, textures, and reflection maps. An MTL file can have multiple material descriptions.
To apply materials in an MTL file, associate the object’s materials with the names defined in the MTL file. This ensures the object renders correctly.
Many 3D software like Caligari TrueSpace support importing and exporting MTL files. This lets you share materials between projects or reuse materials from past scenes. Imported MTL files automatically apply materials to objects.
You can manually associate MTL files with other applications like Adobe Photoshop, even if they don’t open MTLs natively. Right-click the MTL file, open Properties, and select the application in the dialog box.
Programs that open MTL files include free text editors like Notepad on Windows and TextEdit on Mac. Some 3D editing software can also import and export MTL files. If an MTL file is damaged, ask the source to supply another copy.
Blender
Autodesk Maya
Unity 3D