Update announcement:
In the process of writing the manual,
found that VRM SDK has some problem of the compatibility with converting from fbx to vrm of unity 2017 .
Although it does not affect the VRM those had been successfully converted
But to avoid potential compatibility issues and to unify the version,
I think its time to updated engine version to Unity 2018.2.1f1.
The assetbundle build by Unity 2017 can no longer be used.
Must build assetbundle again by using Unity 2018.
The building steps is the same.
If this makes you feeling annoying, please forgive me.