> "I'm taking advantage of this thread to ask a small question about rendering and especially lighting."
Forum threads are not a finite resource, no need to conserve them
Seriously, you have a better chance of getting an answer with a new thread, *especially* because your question is only vaguely related to the OP, so there is less likelihood of connected readers finding and responding to your follow-on.
Now as to your question:
Easiest thing to check first would be to look at the daz log and see what device was used for the renders - perhaps it was on CPU for some reason - if another app had used enough VRAM then perhaps it would fall back to CPU render even if you did not change any relevant settings. (as a side note, if this happens regularly, then try not running other apps while doing daz renders - firefox and chrome are big vram hogs, as are many games. Also try closing and reopening Daz - it does not completely clean up after itself between renders. last resort, restart windows and only use DAZ in the new session - this can eke out the last few hundred megabytes of vram)
Next: lighting sources can make a large difference - especially going from *no lights* (environment HDRI only) to *some lights*, especially if there are objects in the scene with materials that use subsurface scattering.
You can test this a few ways:
- try removing some/any lights you added see if it goes back to previous speed
- keep the light(s) but check the materials on your objects for subsurface, and remove as needed. it is worth understanding that subsurface scatter is going to make almost no difference to the skin of a far-away figure, you will only really see any improvement in "realism" for relatively closeup views.
Finally: I don't have a reference but I recall reading that "distant light" is a 3Delight leftover, and the correct way to do it in Iray is to either use SunSky (for when the distant light is supposed to represent the sun, obviously), or a spotlight setup at a far away location with very strong intensity.
