Another Silo modeler screenshot.  The yellow-highlighted meshes are IDL emitters which are within the camera's field of view, yet are unseen by the camera - remember the unticked visible to camera box in the emitter object's parameter properties?

     This is a wonderful thing.  Why?  Because the amount of IDL cast by the spotlight emitter inside the light housing is quite limited, even with ambient=30, because of its small surface area.  But those star-shaped slices in the spotlights' cones have a lot more surface area from which to emit light.  They can have a pretty modest ambient value and still light the scene.  The reason for having a stack of several is so that if anything is placed inside the cone, even the upper surfaces (head, shoulders) will receive light.

Now, lay this cone aura and star-slice emitter assembly down 90 degrees, and you have a car headlight. :D  Oh, the reason that the aura cones are fluted instead of being simply a circular cone is because the double edge blend will show as streaks ("godrays") of light.  ^^

     Not obvious at first, but there is another piece, the "wall" surfaces (just three rectangles) on the near side of the little set.  If it were not for P9's visible to camera box being unticked, these wall panels would block the camera I used for the demo shots earlier in the thread.  This prop is another unseen IDL emitter.  And it has a lot of surface area indeed.  So much so that even with the ambient dialed down to a small fraction of 1, it emits the background lighting for the scene, and does so evenly and without splotches.  :)

     The moral of the story is:  use large emitters at lower ambient value when you can, and with P9 you can hide them in plain sight.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5