There is a file packagel that includes the Alvin model in 43 separate STL files and Hi-poly and Low-poly versions. Hirez 3MF and unreal engine compatible FBX formatted model files are also available in the package. You can get this 43+MB package from here. As of 27/08/2023, new parts enabling to build later versions of Alvin is also added to the package. Now you can build various versions of Alvin between 1964 and 1984 by using the parts in the package. Free STL is below. If you want all the 43 parts of the Alvin version 1964 to be printed and shipped to your door, you can do it here. If you prefer a single piece Alvin for a very reasonable price you can have it shipped to your door from here.