The representational accuracy of the isosurface meshes produced by marching isosurfacing methods is usually defined by the closeness of the produced mesh to the isosurface given by trilinear interpolation. In this seminar, a new metric that evaluates the accuracy of marching isosurfacing methods is introduced. The new metric is an accurate estimate of spatial discrepancy between a produced mesh and the trilinear interpolation isosurface. Computation of the new metric is also described. Experimental results of the accuracy examination of several well-known isosurfacing methods using the new metric are presented. An analysis of the accuracy and rendering cost of the mesh produced by each considered method is also given. In addition, possible future extensions of this research work are discussed.