How to make a place-able structure:
- Make copies of your structure’s files. These are “PrimalItemStructure_name” from PrimalEarth\CoreBlueprints\Items\Structures (including subfolders, misc for mortar and pestle) and simply “name” from PrimalEarth\Structures. If the structure has an inventory with crafting, you also need to make a copy of the “PrimalInventoryBP_name” from PrimalEarth\Inventories.
- In the PrimalItem, find “structure to build” and set it to your custom structure. In the structure, find “consumes primal item” and set it to your custom primal item. Also in the structure, go to the component tab, delete the default inventory and add your custom one - where applicable.
- Open your PrimalGameData and add your structure to “additional structures to build”.
- If you want to map custom recipes for your structure, you’ll have to not only add them as craftables (just see the default ones for example on how to do this), but create appropriate engrams and add them to “additional structure engrams” in PrimalGameData.
It should work, but I hadn’t tested this in full (in #4, I remapped recipes rather than added new ones).