Trying to render some scenes with Blender 2.70a and the Cycles rendering engine. This renderer uses raytracing and is much better than the internal Blender renderer.
Room with internal light emitting object, external global illumination and low brightness external sun lamps:
Room with global illumination and external sun lamp with high brigthness and small size (hard shadows). Also the floor has a glossy shader that makes some subtle reflections :
This one looks more realistic but it’s harder to remove noise with an external lamp like this because the path the light has to travel to get to the camera is more complicated. Apparently An easy way to remove the noise and make rendering faster in interior scenes is to put an emissive object in the window instead of an external sun lamp.
On this one we try to put an emissive panel in the window and it looks like it does reduce noise. We also add an armchair to test including models. The drawback of using the panel is that we loose the hard shadows that were very good looking in the previous image:
By making the panel transparent we can combine the two sources of light in the same scene getting the best from both of them:
Trying a different floor texture and applying a plaster material to only some faces of the wall:
Added doors and furniture to see how it looks:
Endless 