Hi - unfortunately I simply have never been able to solve this problem, even moving the geometry close to the origin. Rhino is so amazingly awesome in most every way (nothing else comes close imo) but the shadow issue is a huge failing. Honestly, real time instant shadows in rendered or shaded viewport should work in Rhino but always “detach” from originating surfaces. Adjusting clipping planes sometimes reduces the issue, but I’d personally like to put in a pitch that McNeel look at trying to get quick architectural shadows (I’m not talking about ray traced views and long processing shadows) to where they have been for years in Sketchup (crisp, clean, instant in real real time). I do literally everything in Rhino but export to Sketchup for the sole purpose of getting good shadows… Matthew