1.16 forge change block model using blockstates code example

Example: minecraft modding blockstates

switch (meta) {
    case 0: { ... } // south and on the lower half of the block
    case 1: { ... } // south on the upper side of the block
    case 2: { ... } // north and on the lower half of the block
    case 3: { ... } // north and on the upper half of the block
    ... etc. ...
}