Geometric Accuracy

Figure 5: Overview and solution for the geometric test case.

This model consists of 3 cubes and a wedge on a ground plane (Figure 5). It contains a few of the more common geometric problems in models. The leftmost cube penetrates the ground plane by 1% of its height. The rightmost cube is raised above the ground plane by 1%. A corner of the center cube sticks through the ground plane as well. The center object is a wedge viewed from the thin side. All objects are rotated slightly from alignment with the ground plane axes. Many rendering methods that store energy on surfaces or volumes will have trouble with light or shadow leaks near the point of the wedge. Some ray tracing based approaches using tolerances may exhibit a similar problem here as well, as the shadow rays may start on the wrong side of the wedge. The cubes check the robustness of meshing algorithms.