you seem to have a light or a reflective surface that is aimed at that area. probably a light.

Not a light no. I did put a spot on it to try and define the feature a bit, but the bright eyes effect was there before (and can be produced with only one light). What would a reflective surface be? That's what it looks like to me, as though the underside of the brim is reflecting light onto the eyes. What settings turn on/off a reflective surface?

There are no ray-tracing type of reflections in P4. The only "reflection" reference in P4 is Reflection Mapping which maps simulated reflections on surfaces but does not bounce light and would not create the effect you are getting. Is "Cast Shadows" turned off in the hat's properties or for the spotlight located above and in front of the figure?

Nope. I've checked them many times. (btw, this same thing happens quite often with hair too.) Apart from the reflection thing it also seems as though the light is somehow getting through the object as though there were a gap (there isn't). This is really starting to annoy me now. Oh, btw I'm using pro pack if that's relevant (I might try installing a second copy without pro pack?)

Lights seem to "leak" thru holes in P4. I've had this problem lots of times, for instance with my Cargo Box (Free Stuff) which is also lit up inside at certain angles. I seem to remember that someone (geep?) posted an explanation/solution to this, regarding my box, but I can't find that thread again, so I might me imagining things :o( Is the hat solid inside?

Duplicated your test and got rid of (most of) the light leak by zooming-in Lite 2's ShadowCam to about 15%.

Wow Nance. I would NEVER have thought of that! Thanks :o) This leaking is really one of the things that have bothered me in Poser. Now I know a workaround/fix :o)

Still don't understand why the intersection causes Poser to treat the square like it has a hole in it. I've just made a hard edged shadow around a hole that really shouldn't be there in the first place.

That looks like a fix to me (assuming I can duplicate it at home :) The slight halo will be hidden by the tilt of the head in my original picture anyway so that looks like it might just the ticket. Thanks.

Works pretty easily with spotlights, however, keep in mind that for infinite lights the ShadowCams are reset each time you move the light or increase the overall expanse of your scene in the universe. After either of these changes, the Infinite lights' Shadowcams will automatically zoom out again, readjusting to include all objects in the universe that have "Cast Shadows" turned on in their Properties. btw - This shadowmap anti-aliasing is also the source of the frequent difficulty with getting proper ground shadows, and why turning off CastShadows for the Ground will usually solve the problem. Doing so prevents the ShadowCams from automatically zooming way out to include the entire Ground prop.

Nance, thanks very very much for casting some shadow on this. I've had big problems with Poser 4 shadows. It's very nice to have some understanding of this problem at last.