This image was put together for the sake of this tutorial in an attempt to show how I go about creating various materials. The final image is meant to be in the evening and some of the materials are slightly adjusted for that. However in order to better see what is going on, I have rendered a more noon day lighting for each of the materials dealt with. As this is meant to showcase the Total Textures CD's (a very good collection of textures imo), I will only focus on those materials that are heavily utilizing them.
I will start with the Building Parapet material (Apartment-Parapet.jpg) as a slightly more in-depth introduction into what goes on in a material. To start off with I used a Standard Material with a Multi-Layer shader type. I use this for most all metal materials. This material has a dull Specular hit and a 50% Diffuse Level. As for the Maps, I use a lot of Mix Maps. In the Diffuse Maps, I have a Mix map (Edge Weathering) mixing with an old painted metal map (Chipped Paint – pla004.jpg) using another map (pla004b.jpg) as a Grunge Mask. If you notice, the Grunge Mask is the Bump map for the Chipped Paint map. I tend to do this often as it uses the natural color variations in the images to from a more natural look to the mixing. The Edge Weathering mix consists of the overall color (Rough Metal) using the ColorCorrect Map that is being blended with a more raw version of the Rough Metal map using the Edge Mask Mix map. The Edge Mask Mix map consists of a Noise map and the f-Edge map. The f-Edge map works on the smoothing angles of the mesh and colors all hard edges a specified color. In this case I left it the default white. This makes a procedural mask at all the parts of the mesh that would be prone to heavier weathering effects. To help break up the effect, the Noise map is placed in Color #2 slot (Color #1 slot remains its default color). The Rough Metal map is used as both a Specular Color and Bump Map. For bump maps, I often lower the Blur amount to values of .5-.75 to give a little sharper bump effect. This can cause problems if animated however, so keep that in mind. As for the plugins used here;
Color Correct is a great freebie found here http://www.cuneytozdas.com/software/3dsmax/
And f-Edge is a very useful and inexpensive plug-in found here http://www.ddag.org/
Next I want to address another map that is used extensively in my materials. The Reflection Map setup (Reflection-Maps.jpg) This is basically a way to fake an High Dynamic Range Image using Low Dynamic Range Images.
Go here for a more in depth look at the process http://www.charleycarlat.com/Tutorials/FakeHDRI.jpg
Basically the idea is to have am Environment Map that will seamlessly join itself. For this I used two sky images for Total Textures Vol 3 and in PhotoShop created the Color image shown. Next I create an exposure map my converting to grayscale and adjusting the image to isolate the areas of most intense light from least intense light. In the Mix map in max, I combine these maps by adjusting the outputs of the Color #1 (Dark set to .2) with Color #2 (Light set to 3) to form the dynamic range (or exposure range) desired. The Exposure Map is used in the Mix Amount slot to blend the two.
Now to get back to the materials. The Aparmtent-Doors.jpg shows the one color of the typical material for the doors. For this the shader type is not set to multi-layer. I wanted the material to have a more aluminum look to it which doesn't need much if any lowering of the Diffuse Level. Also, the specularity can easily be taken care of with a single specular hit. Also, there are many of the same Mix Map setups described above. What is normally done is the Diffuse color maps are put together, and then from that I will place a copy in the Bump map slot. I replace the necessary maps with their bump counterparts and try to Instance all that can be. This map setup is generally good enough to go in the Specular Color slot and in this case an inverted (by way of Output Map) version goes into the Glossiness slot. The Reflection is a Falloff Map set to Fresnel (adjust the IOR to please) with a raytraced map type (VRayMap in this case) set to a single bounce. Then in its Environment slot is placed the Reflection Map described above.
The Metal Sheet material (Apartment-Sheet-Metal.jpg) is almost identical to the Doors material described above. A couple maps where swapped out and there you have it.