BiomesOPlenty/src/main/resources/assets/biomesoplenty/models/block/origin_grass_block_snow.json

{
  "parent": "minecraft:block/cube_bottom_top",
  "textures": {
    "top": "biomesoplenty:block/origin_grass_block_top",
    "bottom": "minecraft:block/dirt",
    "side": "minecraft:block/grass_block_snow",
    "particle": "minecraft:block/dirt"
  }
}