September 24, 2011, 12:08:27 pm
What we're using in Lumion at the moment is called cascaded shadow maps.
They're operate in steps using different resolutions depending on the distance to the camera, ie a crisp and high-resolution shadow texture close to the camera and blurrier and more low-resolution shadow "steps" further away where less detail is needed.
What the Shadows -> Range slider does is to change the resolution and the distances where the various "steps" kick in. When the Range slider is set to its maximum value, the shadows near the camera will be rather low-resolution (pixelated) and all we can do is to filter and blur them on the final renderings, so the shadows at least appear to be smoother than they really are. That setting is obviously only meant for aerial point of views.