[1.20.1] How do I make a custom Smithing Template?

[MrBelieve]

I've been trying to make a smithing template that upgrades gold to rose gold but I don't know how and was hoping to get help here.

[MrBelieve]

i've tried doing this 

public static final RegistryObject<Item> SMITHING_TEMPLATE_ROSE = ITEMS.register("smithing_template_rose", () -> new SmithingTemplateItem( Component.translatable(Util.makeDescriptionId("item", new ResourceLocation(RoseGoldMod.MOD_ID,"smithing_template.rose_upgrade.applies_to"))).withStyle(ChatFormatting.BLUE), Component.translatable(Util.makeDescriptionId("item", new ResourceLocation(RoseGoldMod.MOD_ID,"smithing_template.rose_upgrade.ingredients"))).withStyle(ChatFormatting.BLUE), Component.translatable(Util.makeDescriptionId("upgrade", new ResourceLocation(RoseGoldMod.MOD_ID,"rose_upgrade"))).withStyle(ChatFormatting.GRAY), Component.translatable(Util.makeDescriptionId("item", new ResourceLocation(RoseGoldMod.MOD_ID,"smithing_template.rose_upgrade.base_slot_description"))), Component.translatable(Util.makeDescriptionId("item", new ResourceLocation(RoseGoldMod.MOD_ID,"smithing_template.rose_upgrade.additions_slot_description"))), SmithingTemplateItem.createNetheriteUpgradeTemplate().getBaseSlotEmptyIcons(), SmithingTemplateItem.createNetheriteUpgradeTemplate().getAdditionalSlotEmptyIcons()));

but it gives me these errors:

Caused by: java.lang.IllegalStateException: Some intrusive holders were not registered: [Reference{null=air}, Reference{null=air}] Hint: Did you register all your registry objects? Registry stage: ACTIVE

finished with non-zero exit value -1

[NotAJunkie]

Hi!
Have you been able to find a way to add it? I'am looking to add an upgrade template and can't seem to find anything on the internet

[artyl23]

You need to define a new SmithingTemplateItem in your mod.