Blender GIS producing blocky contours in low relief areas

Hi All,

I’m experimenting with hill shading using Blender GIS, as discussed in this tutorial:

I’m following the process outlined here but am not completely happy wit my results. A problem that I run into consistently is the appearance of blocky ‘contour lines’ that show up in low relief areas of my projection. I don’t see this in the examples rendered by others online. Any idea what causes this and how to avoid it?

Screenshot below. Gridded to 10 feet, subsurf set to 11.

Overview:


Zoom of contour-like artifacts:


Attachments