The Model Viewer can be used to view and test models.
The tool allows playing animations, changing the age (dirt and rust overlay) and the color of a vehicle as well as showing the different logos. Also, passenger load (seats) can be tested. Please note that it's currently not possible to test cargo load indicators.
The Model Viewer also includes an option to create screenshots and GUI icons.
Hint: The currently open model is automatically updated (reloaded) whenever the mdl file itself or one of the associated meshes, groups, materials or textures is changed.
Download the Model Viewer here (zip archive). Extract the content of the zip archive into the root folder of the game along with transportfever.exe.
The Linux version can be downloaded here (tar.gz archive).
The vehicle stage mod contains streets and tracks. It is required for the Model Viewer's screenshot functionality to work properly. Download it here (zip archive). Extract the content of the zip archive into the mod folder of the game.