The last few weeks we have been busy texturing our robots, which for me has proved alot more work than expected. The reason for this is that we need our materials to be as realistic as possible since we’ll be compositing them into real life footage. This means I’m spending alot of time creating Specular Maps, Reflection Maps, Realistic Bumps and Displacement Maps. Take worn out metal textures as a example:
( which, obviously, we’ve been creating alot of xD): Your Diffuse material might give you some idea of what kind of metallic look you’re going for, but it alone won’t be good enough for a realistic light-setting.
What we need to do to enhance this material, is to mask out less Reflective and Glossy areas. Also we need to emphasize the scratches and rust-patches by adding a bump. The reason we need to do this is quite simply ( take a look at our worn down car ) because the light does not reflect evenly on a worn down surface. Rust does not reflect the same way polished metal does and it will corrode the metal and possibly leave a rough edge where your car-paint is scraped off. If you have dirt splashed up from a dirty pond covering your metal, it will be less reflective, and leave a layer of fluid which means a un-even surface. So when I make my diffuse map, I always think ahead and put these different elements in layers.
The above example is set up like this:
Layer 1 is the colored patterns
Layer 2 contains the base Metal texture with basic scratches
Layer 3 Rust Patches
Layer 4 Splashed Dirt from ponds.
I do this because it makes it so much easier to mask with accuracy. You can mask it with your wacom or mouse from scratch if you absolutely must, but it will be ten times the work, and will proably never be as good. So adding a Reflection map, modifying our different layers, you’ll notice a couple of changes. The Reflection is overall sharper, because of the brightness of the map, but the black spot ( being rust ) in top of its head is masked out of the reflection, as well as most of the letters. You’ll also see an example of the dirt being masked out of the sharp reflection. As you have probably guessed, the brightness of the image controls your reflection amount. As you make these kind of maps, picture the contrasts of the image as a controller ranging from 0 to 100% where 0 is black and 100 is pure white. This controller is a extension of your Vray settings. Example: to produce a Reflective glossiness value equalent of 0,5 ( Vray settings) you need to make your map 50% gray. 64% gray to produce a value of 0,65 and so on.
Adding a Specular map to the Reflective glossiness sub-material now, we’ll even out that sharp reflection and bring out the scratches in the metal. Even without a bump map, you begin to notice the material getting the depth it needs to look somewhat realistic. The text is now completely masked out and gets a matte look. Make sure your maps line up, This shouldn’t be a problem if you have layered them properly. You’ll notice the Areas which are supposed to be red ( as seen in the diffuse map) have a darker color, and will be less glossy. The idea behind this is that Red is a less reflective color than the metallic gray.
Finally, add your bump. Scratces will need a darker color as they punch into the metal, while spills or dirt is a overlayed fluid and will extrude out from the surface, thus needs a brighter color. Having your dirt on a layer it will be NO problem for you to invert the color, as it is probably Dark from working with the specular/reflection map. I also have a Normal Map, quickly made in Zbrush to liven stuff up and add extra details. Quick tip: If your Bump, Normalor Displacement map lacks details when put into Max, tune down the Blur to a minimum (0,01) in the Bitmap sub-material. You might also try experimenting with your RGB offset.
With the Bump and Normal map on we can see our scratches get a little more depth and our dirt pops a wee bit out. Its the little things that can make all the difference.
This might not look like much work, but it actually takes quite a while when you need to do it for all the parts of a big robot. Its all worth it when you put the model into a awesome scene with HDR lights and so on, and if you ask me, I’d say its essential when youre making the kind of short we do. I’ll Post the finished model with texture later, so you can see the results from doing this stuff. Remi out…
