Using the Enhanced Lighting Engine, you can produce realistic substances in NWN. In addition to values provided by Soren in the original writeup, this page offers a place to put surface properties for common substances for builder reference.

How To Help

You can help add to this list by finding surface properties from such places as Remote Sensing articles having to do with Geology or Urban Planning. There are also many articles concerning anthropogenic climate change which provide reflectivity values for man-made substances used in construction. Other topics include Lab Geochemistry or Mars Surface Studies.

Often that information is shown as a graph in nano- or micrometers. The ranges you're looking for are the visible light spectrum between 400 and 700 nanometers.

Reflectivity is different for each wavelength of light. Human-oriented RGB colors are ranges of wavelengths. To get an idea of how the human eye would see reflectivity we can use the range of 420-440 nm (0.43 um) for blue, 534-545 nm (0.54 um) for green, and 564-580 (0.57 um) for red. When you look at a graph of reflectivity values for a substance, you'll be looking in that very small range, often to the far-left of the graph.

You may run into other terminology such as emissivity or reflectance. Emissivity is the percent energy released from an object after being absorbed by that object and is not the same as reflectivity but the term has often been used in place of reflectivity. Just be careful you're not reading emitted wavelenghts instead of original wavelenths. Reflectance is often used in place of reflectivity. Both represent a fractional value of reflected light vs the original light, so it doesn't matter that they represent different dimensions of analysis. In any case, the values you're looking for are in percents, not normalized values, or offset normalized values, which will both give you very wrong specular maps.

Values on the tables below are given as both color-channel values, and as an average for use with grayscale specularity maps. NWN:EE specular maps are grayscale maps, so you can use the average column, or if you have specific lighting in your area, you can use the column which best represents that lighting.

As always, your roughness map will determine just how shiny the object is, but this value sets your base for a perfectly smooth surface. That being said, remote sensing values below are extremely zoomed out, so a very rough surface looks more like a very flat surface. In reality values pulled from remote sensing will have a portion of the roughness value inside the specular value, so you may need to adjust these slightly. References for lab samples are most often powdered, so they represent a surface with 100% roughness at the macro-scale, but the device being used to collect reflectivity values is instead taking the average of all surface orientations for all grains viewed. So again, you may need to adjust the values slightly for lab-made minerals and power samples.

Rock Types

Specific Minerals

Man-Made Substances

Plants