Today’s building envelope is a complex system in which design goals must be balanced against structural requirements and manufacturing accuracy. Although the AEC industry increasingly requires Building Information Modelling (BIM), façade engineering still has a significant technological gap. This thesis examines the challenges of integrating different digital tools, particularly the gap between BIM’s large-scale coordination and the fine tolerances required for actual construction. From a Façade Consultant’s perspective, this research finds that reliance on BIM alone is insufficient to address the complexities of building envelopes. BIM is strong at managing overall shapes and connections, but it often cannot handle the fine details required for manufacturing, such as glazing tolerances, gasket compression, and bracket adjustments, without making the model too complex.