Well,I have load the obj model like the example  with it's own texture.

The BlockState file is 

Quote

{
  "forge_marker": 1,
  "loader": "forge:obj",
  "defaults": {
    "custom": { "flip-v": true },
    "model": "mytestmod:testobjblock.obj"
  },
  "variants": {
  }
}

MyQuestion is How can I scale it?

I try in "defaults" or "variants" , but it didn't work.

8 hours ago, ntr117 said:

How can I scale it

I know that JSON models provide a way to do it via the transforms section but the best way to do it is definitely to change your model to the correct scale

 

54 minutes ago, Cadiboo said:

I know that JSON models provide a way to do it via the transforms section but the best way to do it is definitely to change your model to the correct scale

maybe this is a solution，but doesn't model in in gui,model in handheld has their own scale？