As for the model viewer, it might happen to mess up the shape (usually always happens to me). Fix it by deleting the .msh file it generates first and then reload it and it will look like it should (assuming this is the same issue).
I did that, The shield was rescaled. so it was actually fixed, but there is still the shield only, so the other objects are missing.....

and I realised, that it made only MAT file, the Msh file was missing either... What is this, I didn't know it was that difficult to make a custom model ;(
As for the model viewer, it might happen to mess up the shape (usually always happens to me). Fix it by deleting the .msh file it generates first and then reload it and it will look like it should (assuming this is the same issue).
I did that, The shield was rescaled. so it was actually fixed, but there is still the shield only, so the other objects are missing.....

and I realised, that it made only MAT file, the Msh file was missing either... What is this, I didn't know it was that difficult to make a custom model ;(