Simply buying items from merchants can be prohibitively expensive. It can be much cheaper to create items by purchasing diagrams that show how they’re constructed, gathering up the materials, and then paying a craftsman to make the item for you. Of course, not every item has a diagram, and some diagrams are difficult to obtain. On the other hand, almost all of the best equipment in the game can only be manufactured from a diagram with the right materials.
Most diagrams can either be found as loot or purchased from a merchant. You can obtain diagrams for basically any sort of item that isn’t made primarily through alchemy. This includes equipment, consumables like traps, enhancements, and (recursively) certain common crafting materials like oil. Once you have a diagram you want to manufacture, make sure you have the materials required to craft it.
While there are certain items in the game like oil and leather that are used only in crafting, basically anything in the game can end up being required to craft a diagram. This includes many monster drops, certain runes, and in rare cases, even full pieces of equipment. Most item diagrams call for a blend of common and rarer items.
Once you have a diagram and the crafting materials it requires, find a craftsman. Craftsmen do business in settled areas and are usually marked on your in-game mini-map. Generally, while playing in the main game, you have access to one major town or city in each chapter, where a few craftsmen ply their trade. All craftsmen are also merchants, often selling a wide selection of diagrams and crafting materials. You can consult the walkthrough for specific locations and shop lists for the craftsmen available in each chapter.
Once you have a diagram, materials, and a craftsman, you can make an item. First, speak with the craftsman and ask him to create an item for you. This takes you into the game’s crafting interface. Simply select the diagram you wish to craft with your confirmation button. If you have the materials required to make it in your inventory, then you can pay a fee to craft the item. Your crafting materials are consumed, but in exchange you get a new item.
It can be tremendously useful to acquire diagrams and stockpile materials necessary for crafting items you use frequently, like runes or certain armor enhancements. You also want to obtain diagrams for rarer materials required in crafting, like robust cloth, essence of water, and studded leather. Otherwise, it’s best to keep an eye out for diagrams that let you make unique equipment that cannot otherwise be purchased. The items that result from these diagrams are often unusually powerful, though not necessarily better than certain rare items you find only as loot.