Pulmonary segmentectomy-level variations in the three-dimensional (3D) architecture of the bronchi and pulmonary vessels are much wider than those at the lobectomy level. Presurgical simulation with sharing of necessary information is believed to reduce the surgical time and number of detachment procedures required. For such simulations, the author’s group developed homemade software that: 1) reconstructs the shapes of the bronchi, vessels, lung, and tumors as simplified 3D images such as sequentially connected cylinders with branches and membranes from digital-imaging data on a personal computer screen; 2) allows surgeons to input data on the initial and terminal points, diameters of cylinders, etc. continuously by moving computed tomography (CT) images up and down; and 3) permits these data to be read by modeler shareware on the Internet. Although conventional 3D images from CT data are reconstructed by a volume-rendering method, those of the software developed by the author’s group are made using a surface-rendering method. This article explains the present status of and future trends in the actual processes of simulated surgery including segmentectomy and navigation, applications of newly developed operative procedures, and results of data analysis of more than 500 cases.