Sorry about this I decided to edit my original question and add this on but by the time I submitted it you had kindly answered my first about 99.99 settings. Here is the second part resubmitted so that hopefully you can respond...:
Mike - thanks for the rendering comparison.
The thing that strikes me about your comparative renders is that in the roughness 99 version it looks as though most of the scenes light energy comes from the windows in the center of frame. - The light energy from the sun that comes in from the right side windows is very diminished in terms of its overall light energy contribution in the 99 roughness rendering. The lambertian version better indicates the overall balance of light energies in the scene (assuming you didn't change the emitter settings.) - I would suggest that there's something wrong with the roughness 99 material if it is over amplifying first bounce light energy over and above the larger energy contribution of the sun.
If in reality you made this scene with say matte clay objects and replaced them with lightly polished ones I don't think the viewer would think the sun had moved from the side to the back of the room.
This is not meant to be a criticism of your work more a concern over how maxwells materials influence the scene overall light distribution.
- By choo-chee
- By Andreas Hopf