  This work describes and demonstrates the operation of a virtual X-ray
algorithm operating on finite-element post-processing results which allows for
higher polynomial orders in geometry representation as well as density
distribution. A nested hierarchy of oriented bounding boxes is used for
preselecting candidate elements undergoing a ray-casting procedure. The exact
intersection points of the ray with the finite element are not computed,
instead the ray is discretized by a sequence of points. The element-local
coordinates of each discretized point are determined using a local
Newton-iteration and the resulting densities are accumulated. This procedure
results in highly accurate virtual X-ray images of finite element models.
