We have already determined that the light sources that illuminate our room are positioned correctly but the room is too brightly lit and lacks contrast. We will remedy this in the following steps.
First, open the menu and add the Ambient Occlusion effect from the Effect … list. This effect works the same as the shader of the same name that can be applied in a material’s channels. However, applying the effect here will result in all scene objects automatically being affected. Set the Maximum Ray Length value to 1000 - this value is most effective for our particular scene. Also, reduce the Contrast value to -20%, which will avoid generating areas that are too dark.
Finally, enable the Evaluate Transparency option. This will ensure that objects in the room that have transparent materials will be properly evaluated by Ambient Occlusion when it darkens certain regions. The result is shown in the image below. The top of the image shows the scene rendered without Ambient Occlusion being enabled; the bottom of the image shows the scene rendered with Ambient Occlusion enabled. The difference can be seen in particular beneath the sofa and the sofa table. These objects no longer look as if they are "floating" over the floor. The region around the door and the elements around the television have much more depth. Nevertheless, the ceiling and walls are still lit too brightly and this is what we will turn our attention to next.
We will now add another effect from the Effect … menu - Color Mapping. Color Mapping will redistribute the light in the scene so that values greater than 100% will not be generated. What makes this possible is the fact that Cinema 4D renders with a 32-bit color depth, even if the image is subsequently saved at only 8 or 16-bit color depth. By manually modifying the Color Mapping parameters, regions that are too dark or too bright can be adjusted accordingly. At the top of the image below you can see the settings used for our scene.
As a rule, the Exponential and HSV Model options should be enabled when applying the Color Mapping effect. These will create a natural falloff of brightness and maintain color values when brightness values are adapted. The Affect Background option on the other hand should remain disabled. This option is only relevant if you want to adjust the brightness of an image projected onto a Sky or Background object. The remaining two settings are for multiplying dark and bright image regions, respectively. A Dark Multiplier value greater than 1 will increase the rendered image’s brightness; conversely the Bright Multiplier setting can be used to darken the image. The results of the modified Multiplier settings can be seen at the bottom of the previous image.
We have now successfully textured and illuminated our room.