Shadows disapear when topography is added to model

Hi there,

Whenever I turn on my topography layer (a nearby mountain range), all of the nice crisp, dark shadows cast by the buildings disappear. I know because of a previous sun study that the mountains do not cast a shadow throughout the entire day on the area so I’m wondering why the shadows on the ground disappear when the topography layer is turned on!
See attached Rhino 6 model and images below for reference.

What the rendered shadows look like when the topography is turned on (what I don’t want)

How I want the shadows to look when the topography layer is on!

Mountain Range Model.3dm (17.1 MB)


your scene is unnecessarily massive, and a very very long way from the origin-

Once I reduced the amount of data that was not visible, moved your scene to the origin and adjusted the shadows in rendered mode as shown, the shadows look like you are expecting-

(i neglected to turn edges on, but that makes it look like your sample- )