In this paper we advocate the use of a focal region- guided feature-based olume renderer that offers an alternati e for isualization of internal structures of olumetric data.We describe this promising technique for communicating the first impression of object shape or contour while at the same time pro iding detailed information of olumetric data with the use of lens-like focal region.We designed a method for generating object contours and enhancing olumetric features to depict context information out of focal region based on gradient volume.In the focal region,we render interesting volume data using the direct olume rendering method.The rendering is guided byfocal region through which we can specify what subset to render.The connection between the structure of inside and outside of focal region gives a better understanding of spatial relationship.This is to better communicate the existence,form,and location of underlying targets while minimally occluding them.