In the last five years, many hospitals in Japan have created three-dimensional (3D) images from computed tomography (CT) data from patients who have undergone liver resection to share the images of liver structures with the surgical team and analyze the liver volume based on portal perfusion. However, using the previous software packages, the 3D liver model was fixed and rigid. Therefore, we developed novel 3D simulation software, called Liversim, to visualize real-time malformations of the liver. There were no marked differences during the process of liver resection between Liversim and actual surgery. Virtual liver resection showing real-time malformations of the liver using Liversim is useful for the safe performance of liver resections.