This paper presents a commercial real-time ultrasound simulator. An ultrasound volume is constructed from real ultrasound images in an off-line pre-process. Then simulated images are generated by slicing the volume in real-time. Such images can be computed very rapidly, including a post-processing enhancement. In most cases these synthetic images are indistinguishable from real ultrasound images.This method needs to deal with the fact that an ultrasound image has view-dependent features and an acquisition-parameter-dependent character. This fact is two-fold: firstly, the pre-processed volume dataset includes some unwanted view-dependent features which should be removed. Secondly, the generated simulated image from a given arbitrary direction should be enhanced to include the appropriate view dependent features.The paper describes the concepts of the ultrasound simulator, the real-time imaging algorithm and the off-line formation of the ultrasound volume dataset.