ArticlePower BI in Fabric: Semantic Models, Direct Lake, and the Copilot Era
Power BI in Microsoft Fabric turns lakehouse and warehouse data into reports, dashboards, and apps built on a semantic model. This article covers how workspaces, capacities, and semantic models fit together, how to choose between Import, DirectQuery, and Direct Lake storage modes, the internal read path and flavor differences behind Direct Lake, the large-format semantic model machinery (VertiPaq segments, dynamic memory eviction, on-demand load) that governs performance at scale, and what's changed with Copilot-era authoring — AI-assisted DAX, preparing a model to be AI-ready, the Q&A-to-Copilot transition, and the PBIR report format for source control.