This is a 3d view of the smallest Japanese rock garden at the Ryogen-in temple: Totekiko.
The scene is being modelled with Blender and I’ve rendered this image with Octane until it reached 4000 samples per pixel.
The sand is modelled by applying a custom displacement map to a subdivided plane. I did the map with Inkscape (only gradients) in order to be able to modify the heights easily if wanted:
For the rocks I used this technique from Thomas Schloegl: