Calclavia Core is a library package created by Calclavia. It contains the Resonant Engine, a framework by the Universal Electricity team formulated to make modding easier. It contains a lot of reusable code; containing ore and basic item generation, allowing developers to avoid creating duplicate content. This package of common code is required for Modular Force Field System (Calclavia), Resonant Induction, and ICBM to launch correctly. This is commonly used together with Universal Electricity Core.