Spotlight light propagation distance (in iRay) with Ray Distance

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Okay, I have a small object in front of another larger object, in a dim room.  Both objects are similar enough in color (sort of a dark brown) that the smaller object is kinda disappearing against the larger object.  I hit upon the solution of pointing a small spotlight at the smaller, closer object, and then adjusting the light cone (as seen by its prop adjustment imagery in the Viewport) so it ends a tiny, tiny distance past the smaller object, that way the smaller object now has a small amount of extra light shining on it, so that it "pops" a bit more noticibly agaist the background formed by that other, larger object.  My understanding of the significance of the visibly-shown end of that light-cone-object in the Viewport (that causes the cone-shape symbol thingy to shrink shorter in Viewport when you dial Display, Scene View, Light Cone, Ray Langth down) was that the light would propogate out to the distance that that symbolic reresentation of the cone size and shape in Viewport.... and then simply STOP COLD the instant it got that distance out, as if the beam of light had slammed into an invisible barrier.

But.... I'm seeing a shadow applied onto the larger object, which is clearly shaped like the object I'm trying to light up.  It is spoiling the shot I'm trying to make. I've dialed the light cone back, visibly, to well shy of the object I'm trying to light up contrastingly... and I'm STILL seeing the shadow of it on that other prop.  Am I missing something?  I thought the entire idea behind the Ray Length slider was to adjust what zone-of-distance you wanted the light to be in, so that you could place an object inside that ZONE, and have the light exist ONLY inside that zone and to not continue one iota past that zone.  oO

 

Richard Haseltine

In Iray light falls off by the inverse square law, and objects always cast shadows (in Photoreal mode, you can turn shadows off in Interactive but that has significant downsides).