Visualizing 3-D symmetric tensor fields using a type of surface icons

We design a type of surface icons to visualize 3-D second-order symmetric tensor fields which are tangent to two of the three orthogonal eigenvector fields and orthogonal to the third one. We use the conception of discrete normal vectors and construct a space triangular mesh to approximate the desired surface icon with the discrete normal vector parallel to the given eigenvector field at every vertex. Our surface icons represent the information of tensor fields along them and reveal the continuity of the tensor fields to a greater extent than point and line icons, so help to improve the perception of complex eigenvector patterns in symmetric tensor data sets.