Efficient computer assisted surgery dealing with soft tissues remains a complex task. In most cases, the preoperative information such as 3D organ reconstructions and the planning built upon are no longer valid during the surgical process itself due to the deformations of the organ of interest. In this article, we describe the foundation parts of a framework that enables updating preoperative 3D models with intraoperative measurements in case of liver resection. The technique can be summarized as follows. During the planning stage, the discrete skeleton of hepatic veins is created out of the CT-reconstruction. It is used at time of surgery as the core component of an elastic registration between the model and measured points located on vessels centerline. Intraoperative data points are automatically computed from navigated ultrasound images with a real-time segmentation method. Our approach was tested on simulated and real datasets and has demonstrated to be fast and effective.