Btw, here's a quick example I just did for you with a sphere, ground plane (a cube actually) and a spotlight. I left the raytracing defaults in render globals and in the spotlight's attributes, it's setup like this:
no decay
cone angle 40
penumbra 10
dropoff: 0
raytraced shadows on:
Light radius: 2.009
shadow rays: 10
depth limit: 1
You should experiment with lower values....increasing radius or rays will slow your rendering, even for simple scene such as the one I did.
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