I'm in minecraft version 1.12.2, and when I save a new model... it appears in my inventory but when I try to equip it, it doesn't appear. I know the mod is working though because the model appears on mannequins. I have these mods installed: Chisel and bits, Mr. Crayfish's Furniture, Left 2 mine, MCMultiPart, MorePlayerModels, optifine, world edit, Armourer's workshop.

Quick edit: I actually fixed it, it's just that the Left 2 Mine mod breaks it. so I ask of armourer's workshop to be able to be compatible with the Left 2 Mine mod.