--- id: segmentation-index title: Segmentation sidebar_position: 1 summary: Migration guide for segmentation architecture changes in OHIF 3.9, covering the shift from tool group-centric to viewport-centric architecture to support advanced visualization capabilities and more flexible segmentation handling. --- import DocCardList from '@theme/DocCardList'; :::info This migration involves significant architectural changes to the segmentation system. While we typically aim for incremental updates, the shift from a tool group-centric to a viewport-centric architecture was necessary to support OHIF 3.9's advanced visualization capabilities, and more flexible segmentation handling. Don't worry - we'll guide you through each change step by step! :::