There are quite a few very useful features in IRender nXt with advantages that aren't necessarily obvious. One such feature is "Auto-Reflection". Auto-Reflection uses material name pattern matching to preset reflection intensity and sharpness. Many of the materials in the SketchUp library are included in the standard list.
Pattern matching means that any material assignment in the SketchUp model that includes "wood" in the name will be rendered with a reflection intensity of .3 and sharpness of 1.00. All of the preset values can be adjusted and it's easy to add to the list. So rather than remembering, reworking, or experimenting with realistic reflection values for materials that you use frequently, try Auto-Reflections. You'll save a lot of time and get consistently realistic reflections in your rendered images.
As an example, the following image was processed with Auto-Reflection set to "Off". When I put this little model together, all I did was assign SketchUp materials.
Then I turned Auto-Reflection "On" and processed a new rendering.
Want to learn more? Auto Reflection