Lighting and texturing a muppet-style character head.
In this tutorial, we’ll cover some texturing and lighting techniques that I have found useful in my own work. Some of the techniques discussed come from various readings while others are the result of trial and error. Ready? Here we go…
Figure 1
Meet the cast
Figure 1 shows the model that we’ll be using (although any simple model (or even a scene with a strong focal point) would work fine). I chose a simple model because it is much easier to see changes from one rendering to the next in a simple model; as such, it’s hoped that by choosing a simple character you’ll be able to more readily see the desired changes from rendering to rendering.
The character is currently illuminated with the default Max lighting and has no textures applied. Lets fix that now.
The chicken and the egg
Before we start we need to decide how to deal with the “chicken and egg” problem of texturing and lighting: the effectiveness of a texture is (unfortunately) dependent on the lighting in the scene; additionally, lighting a completely “blank” model doesn’t really give one a good feel for how effective the lighting is. Because of this dependent behavior, starting with texturing usually requires additional tweaking once the lighting has been added; conversely, starting with lighting usually means tweaking it after the texturing has been applied.
Most of the dependency between lighting and texturing arises from how bump maps, specularity, reflectivity, etc. rely on the light source for their effectiveness. Therefore, it is usually best to add them after the lighting.
So, in this tutorial we’re going to apply the diffuse coloring to the model, switch over to setting up the lights, and then switch back to assigning the appropriate specularity, bump maps, etc.
Staying with in the lines (simple coloring)
The first step is to decide what type of texturing you want: realistic, cartoonish, stylized, or other. We’ll try to create a more “realistic” looking texture with the goal of creating an image which looks like its a “muppet.”
As muppets tend to be a uniform color and bears tend to be brown, I’ve chosen a ruddy brown color (167, 91, 49) for the ears and face (I’ve also locked the ambient and the diffuse coloring together). The eyes are going to be white (255, 255, 255) with blue (90, 50, 220) colored pupils (technically, there should be blue irises with black pupils, but since this is a muppet, we can get away by having a pupil/iris complex) and the nose will be red (223, 49, 49). Figure 2 shows how the “colored” bear looks with the default lights.
Figure 2
Step into the light
Once you’re happy with the coloring (including whatever bitmaps/noise/etc. you want to use for diffuse and/or ambient coloring), it’s time to light the model. We start by changing the ambient color from black to a dark violet color. In “the real world” pure black is a very rare color; as such, removing it from your 3D scenes helps to add to their realism. Since the main lights will be yellowish (218, 218, 192), I have chosen a complimentary purplish hue (18, 11, 25) for the ambient light. Choosing complimentary light and shadow colors in this manner helps to add “depth” (and hence realism) to your image.
For lighting the character we’ll be using techniques borrowed from “standard” cinematography. We start with the key light. As this is the main light source for the model, great care should be taken in its placement. Place it below the character if you want him/her to seem large and imposing, place the light way above the character if you want to make him/her seem smaller and less imposing, place it a little above the camera to achieve a “neutral” amount of imposition.
At this time you should also decide whether or not the light is “motivated” or “unmotivated.” A motivated light has an apparent (or at least strong implied (such as the sun)) source in the scene. An unmotivated light simply exists. Use unmotivated lights carefully in “realistic” scenes because they can make your audience wonder (either consciously or unconsciously) where the light is coming from and therefore can break the viewer’s suspension of disbelief.
In this scene, I’m using a motivated light which could either be the sun or a strong spot light. Because real world light is seldom white or a shade of gray, I’ve set the light’s color to a yellowish hue (218, 218, 192).
As for light placement, I’ve placed it off to the right above the character (See figures 3a, 3b, and 3c). As you can tell from these figures, I’ve attenuated the key light. Real world lights do not go on forever, they all have finite ranges. Adding attenuation to your lights helps to produce more gradations of colors, which, in turn, make the images look more 3 dimensional. I have also turned on shadows for the light. The result of this light (and the change to the ambient light) can be seen in figure 3d.
Figures 3a, 3b & 3c
Figure 3d
Filling out quite nicely
As you might have noticed in figure 3d, even though the ambient light isn’t black, the left side of the model tends to blend into the background. To help address this issue, we add another light to the scene: the fill light. The fill light provides illumination to the model on the side “opposite” of the key light. If the key light is on the right, the fill light will be on the left; if the key light is above the model, the fill light will be below the model (see figures 4a, 4b, and 4c). Usually, the fill light is 1 / 2 to 1 / 5 the strength of the key light. In this case, I’ve set its multiplier to 0.22. For a bit of added color contrast and depth, I’ve also set the fill light to have a bluish/violet color (205, 192, 218). Just as I did with the key light, I have also attenuated the fill light (again, refer to figures 4a, 4b, and 4c). Figure 4d shows the affects of all of the lights we have added so far.
Figure 4a, 4b & 4c
Figure 4d
Backing it up
Although we have filled out the model’s left side, it still tends to blend into the background. To help address this issue, we add another light to the scene: the back light. The primary purpose of the back light is to provide a small sliver of illumination along the back edge of the model to help separate it from the background. I usually create this light by cloning the key light and moving it around behind the model. Figures 5a, 5b, and 5c show the placement of the back light in the given scene. Since I based the back light on the key light, it has the same color, employs attenuation (which I have modified appropriately) and also casts shadows. Figure 5d shows the added illumination offered by the back light.
Figure 5a, 5b & 5c
Figure 5d
