The optical modeling of computational shadowgraph, schlieren and interferometry is discussed. The results of CFD (computational fluid dynamics) and transmission of optical waves through theoretical flowfield are used to generate digital pictures that simulate real observations. Concerning the specialty of the axis symmetric flow, the integral calculation in the equations of the optical model is simplified. A ring belt method is developed to obtain three dimensional integral results from two dimensional CFD results to process graphic rendering of computational flow imaging for axis symmetric flow. This technology provides a better insight into the flow physics and is extremely useful to experimentally validate CFD codes. An example for hypersonic blunted cone flow in ballistic range is illustrated.