In response to the inadaptation and difficulties for architects in the use of engi-neering simulation tools and optimization methods,a method is proposed for graphical perfor-mance evaluation achieved with a developed plugin for Grasshopper as an architect-friendly tool to support design exploration in early stage.The proposed method follows forward work-flow for interactive feedback of performance,focusing on thermal and visual comfort upon a variety of design options.A case study of shading design is demonstrated.The demonstration illustrated an intuitive and graphical process for qualitative performance evaluation,which is assisted by an overall ratio ranking the integrated performance of design options for a quan-titative comparison.Compared with engineering optimization methods that focus on optimal performance-based solutions,the proposed method presented graphical feedbacks on design performance that are interactive with the designer for performance-informed decision mak-ing.In this way,the proposed method stimulates the effective and positive application of en-gineering tools and judgment at the early stage of iterative design.