If you load an image from a Z-Depth screenshot you usually see nasty artefacts in smooth areas from the greyscale levels stepping. I've added a better Bumpmap to Normalmap convertor that creates a smooth result in gently changing areas and a sharp result in more finely detailed areas.
The stepping effect was not great in Curvy 4, but it was really bad when I tried to use bumpmaps in other software - they much prefer Normalmaps and you can simply load Curvy's created normalmaps into other software for an instant render quality improvement.
This realtime screenshot of Curvy 3D 5 shows the new bumpmap tech on shiny plastic and worn metal. Without the bumpmap both spheres would look perfectly smooth.
(You can also see some of Curvy's new realtime lighting tech here)