I have create a very basic blender scene with Suzanne and a modified cube with no UVs and only basic materials. The scene contains about 3 emissive lights.
Using the cycles rendering engine, when rendering the exterior scene (3 lights, Suzanne and cube), blender takes 55 seconds.
However when rendering inside of the cube which contains only 1 emissive light, it takes 3 minutes and is relatively slower. Why is it so?
Even the empty inside of Suzanne which contains nothing takes longer time. Why so? Am I doing something wrong or is it natural?
Note: All the scenes are rendered with exactly the same settings and 6 samples