1:1 comparison of the ‘cliptracing’ (left) and the raytracing (right) algorithms. In the former, polygons were clipped by individual pixels (analytically) and the synthetic image of (22) is very smooth. In the latter, a simple inside-polygon test was used for each ray, which creates discretisation artefacts and the synthetic image is then ‘noisy’. The Lambert scattering law was used in this test.