My goal was to create a document where the main features of 3ds Max are grouped togheter to create daytime / night time renderings of buildings without overloading it with cumbersome step-by-step “click here/ click there” instructions.  It gives some tips and tricks around NPR (Non-PhotoRealistic) rendering as well.

Here it is:

mentalray.for.aec.renderings

This group maintains a database and publishes this data via a program called Optics 5. From Optics 5 you can then export a Radiance Material (*.rad file), which can be interpreted
as mental ray A&D Material parameters.

To convert Optics 5 data into A&D Material suitable for lighting analysis, export a glazing or glass definition as Radiance (*.rad) from Optics 5. You will find this command under File | Export to Radiance File.

Once the file is exported on disk, open it in Notepad and search for a section that looks like this:

void BRTDfunc B530_front
10
0.245 0.281 0.340
0.169 0.197 0.187
0 0 0

The color coefficients (RGB) for the ideal specular reflection corresponds to 0.245 0.281 0.340. The color coefficients for the ideal specular transmission corresponds to 0.169 0.197 0.187. Those values will need to be used as a basis for the mental ray A&D Material.

How to use the provided Microsoft Excel spreadsheet to convert to the mr A&D Material.

To correctly convert specular reflection and transmission from a Radiance material to a mr A&D Material, we need to take into account internal energy conservation methods that are built in the mr A&D Material that are not factored by the Radiance material. In other words, numbers can’t be “plugged-in” as is.

To help you with this task, we developed a Microsoft® Excel® software spreadsheet that will let you do this precisely. The spreadsheet can be downloaded here.

Limitations:

• The Radiance Materials exported from the Optics 5 database does not take into account angular dependency: A Fresnel falloff curve is assumed so metallic-coated glazing systems may be less precisely simulated.
• The Optics 5 database contains optical data measured spectrally. The exported Radiance materials and the A&D materials use RGB colors which are a crude approximation of the visible light spectrum. Therefore, lighting simulations are done within limitations of RGB colors.

Click here to download the Wordfile.txt file for UltraEdit (Right Click | Save Target As…)

Install it in your UltraEdit installation folder:

When opening a mi file you should see something like this: