Select the Advanced light, go to the Parameters pane (or Lighting pane), then under Lighting Control, go to If Surface Is Flagged... and choose "Illuminate Flagged Only."
If you're asking how to actually flag something, there are several methods, but I usually set the Diffuse Strength to 99% of the item I want to flag, then tell the Advanced Light to flag objects with a diffuse strength of 99%: Lighting Control>Flag Surface Shaders With...>Diffuse Strength of...; Diffuse, Ambient, or IOR Value 99%.
Comments
Select the Advanced light, go to the Parameters pane (or Lighting pane), then under Lighting Control, go to If Surface Is Flagged... and choose "Illuminate Flagged Only."
If you're asking how to actually flag something, there are several methods, but I usually set the Diffuse Strength to 99% of the item I want to flag, then tell the Advanced Light to flag objects with a diffuse strength of 99%: Lighting Control>Flag Surface Shaders With...>Diffuse Strength of...; Diffuse, Ambient, or IOR Value 99%.
Hopefully those instructions are understandable, but if you need more detail, I highly recommend reading the Advanced Ambient Light user guide: http://docs.daz3d.com/lib/exe/fetch.php/public/read_me/index/17031/17031_advanced-ambient-light.pdf
Thank you ... thank you ... thank you
its the 99 % wasn't clicking in my brain
thanx for the info Scott :-)