Casts were made of three important blood flow structures: an arterial bifurcation, the upper aorta, and the left ventricular chamber of the heart. A coordinate measuring machine was used to measure and digitize the coordinates of the casts. From the complex measured shape values, three-dimensional volume representations were constructed. Surface volume smoothing and filling was performed by a system developed for a body fitted coordinate, finite volume type flow simulation using its spline function. Visualization of the structures was performed on a graphics workstation. The geometric patterns are now being inserted into the three-dimensional flow simulation package to compute complex flow patterns, wall shear stress and pressure contours.