A bit OT, but thanks @clement for pointing out the rsun format.
I had a precious find in there: I don’t think it is exposed in Rhino UI but one can actually control the intensity of the sun shadow (or Transparency if you like) by manually editing that file:
Try exporting, editing that line and re-importing…
This is very useful, especially for scenes with no Skylight, since now the shadows often are too dark. Changing the Shadow Color from the DisplayMode doesn’t cut it since brighter colors don’t mean ‘transparency’, just a solid color, so often they would cause the effect of the shadow being brighter than lit area…
@Andy - this is yet another display setting that I wish was available in the Sun UI, without tricks.
I know the standard response is “we are trying to make all work out of the box” but the reality is every project is different and making it all work with limited settings is unrealistic (to put it politely ) Please allow us to decide what works best by exposing settings that are already there. Make your “default” as close as possible to work “out of the box” but from there let more advanced or curious users tweak it and even “screw it up” - one can always reset to defaults.
While at it, let’s add a wish for Sunlight Intensity parameter