The scene behind this tutorial is based around an industrial facility of some description, possibly a water treatment plant or pumping station. The design was inspired by numerous images of sewers, dams, storm drains and other manmade environments. I imagined that the facility was no longer in operation and had since been inhabited by squatters. The new tenants have built some temporary shelters which nestle along the sides of the plant and are now connected by a series of suspended walkways. The objective was to age a relatively clean scene by adding Dirt maps and generally make everything look a little older and more dilapidated using 3DTotal's Total Texture collection. The three main components that compose the bulk of the environment and which will form the focus of the tutorial are the wall, pipe work and foreground cabin.
Fig.01 shows the un-textured scene with the main light source located in the upper right by way of an Area Spot, which incorporates some Attenuation. I wanted to convey a sunken chamber that eventually descends to a depth that is almost beyond the filtration of natural daylight. The cabin is housed at a point at which the sunlight is quite dim and requires some artificial light in the form of two bulbs. These correspond with two Omni lights, which have been used to illuminate the walkways and foreground scenery.
Texturing the Wall
Being the largest section of geometry and a significant part of the image, the wall was an obvious starting point. I decided to incorporate mental ray's ProMaterials and, more specifically, the Concrete material. You can see in Fig.01 how this affects the surface of the geometry before the Diffuse map is even applied. The actual Color map was built up from predominantly three textures taken from Total Textures: V2:R2 - Aged & Stressed
The upper-left image formed the basis of the wall with the remaining two being overlaid using either the Soft Light or Overlay blending modes to add variation. Before applying the texture I added some further subtle stains below the ledge that runs across the wall. Fig.03 shows the texture and where it is applied within the ProMaterial alongside the corresponding stains situated underneath the ledge (1). These have been extracted from two Color maps that are part of the V2 collection. The ones marked "1" were color corrected and then set to Multiply at 80% opacity, whereas the lower example was set to Hard Light at 100%.
In order to create the more worn version I incorporated a Composite map into the ProMaterial. This retains the material but allows the inclusion of various layers controlled by masks in order to add dirt and grime without adding to the original texture. The maps can be overlaid in a number of ways using blending modes as well as being color corrected. Mask channels allow control over the location of the dirt and by altering the Coordinate properties each can be placed specifically in the scene. Fig.04 shows the four Composite layers, their blending modes and opacity alongside the masks that govern their visibility. The four scenes on the right show the individual masks and reveal where the corresponding maps are visible. You can see how each one occupies a different position, which is implemented through the Tiling, Offset and Angle.