The interest of timber structures has in recent years increased, primarily due tothe environmental benets of timber. This has created an increased demand forstructural engineers with timber expertise. At the same time the concept of structuralparametric design have become more popular. This new way of working withdesigns enables for architects and engineers to explore dierent geometries in earlystages of a project. However, the combination of a parametric workow and timberdesign have so far been limited due to the complexity of the material.This thesis aims to create an parametric workow within the visual programmingenvironment Grasshopper. This enables analysis of structural design simultaneouslywith a cross sectional and topological optimization of timber structures. The structuralanalysis is performed with Karamba which is a plug-in tool to the Grasshopperenvironment. The design verication based on Eurocode EN-1995 have been manuallyscripted in python components. The parametric model have been applied to acase where the main bearing bearing of a glass roof is to be designed. Three dierentgeometries have been evaluated with regard to cross sectional dimensions andgeometrical shape.The framework with a truss turned out to be a preferable design if only consideringweight, deection and utilization. The truss frame provides the lowest weight and thesecond smallest displacement. Furthermore, a comparison of the structural analysisand design have been performed with the FEM-program Robot. The compassionshow similar results, increasing the reliability of the Grasshopper model and theresults from this tool. It conrms it is possible to perform generative design oftimber structures within the same interface.The Grasshopper model is limited and can not handle all variations of 2D timberstructures. The complexity and variation of such calculations in conjunction with theEurocode have not been implemented during the time-span of this thesis. However,it is general within the limitations of the case study meaning a variety of framegeometries can be evaluated.