Beaver is a tool that allows a parametric structural analysis and design of timber structures according to the European code “Eurocode5 - Design of Timber Structures”. Beaver was thought primarly to work together with Karamba3D, but receives raw structural data and can be used with any FEA plug-in inside Grasshopper environment (Such as ix-Cube and Koala). With this workflow, one can develop a parametric design process that goes from architectural conception to structural detailing in one single software interface. This process can be usefull for both complex parametric structures and ruled modular traditional structures, allowing the user to optimize structural arrangement, sections and connections based on a consolidated structural safety limit state code. Beaver was conceived at the Polytechnic School of the University of São Paulo - Brazil, and developed by Eng. Márcio Sartorelli and Eng. João Tavares Pini (joao.pini@alumni.usp.br). Design and logo by the great artist Raquel Silveira.