Essential Blender- P21 pps

Bottom light is the light we're least accustomed to seeing. It has an intense impact when used, making objects look completely different and often sinister. Figure 5.3. 06: The bust lit from beneath. Shadows Shadow control is half of good lighting. No shadows If none of your lamps have shadows turned on, it will look like your objects are floating, as in the illustration below. To achieve any kind of believability, you need some kind of shadowing. However, you don't necessarily want every lamp in your scene to cast shadows, for both technical and artistic reasons. Figure 5.4. 01: A render with no shadows at all. Hard vs. Soft Shadows Turn on Ray Shadows for a standard Blender lamp, and you'll get hard edged shadows. Very seldom are true, sharp shadows seen in reality. In the physical world, the smaller the light source, the harder the shadow, and vice versa. Of course, that means that the 100% hard shadows generated by Ray Shadow don't really exist in the real world, simply because they would require an infinitely small light source. There are countless examples of images that have been ruined by hard shadows from several light sources, crossing each other and confusing the eye. If the artists had paid as much attention to shadowing as they had to the rest of their scene, this would not have happened. A guideline to remember: every shadow is soft, even the ones that you remember as hard. We are not really used to seeing completely sharp shadows, so our eye finds it distracting in rendered scenes. It is especially noticeable in close-ups, where shadows are always soft to some degree. To illustrate the difference between hard and soft shadows in real life, look at these two almost identical photos: Figure 5.4. 02 The shading defines the object more clearly, but the hard shadow actually becomes part of the composition of the photograph. Figure 5.4. 03 The object is less defined, as the light has been spread out by the more diffuse source. There are, however, no hard shadows to distract the eye, and it makes the photo softer and the subject more dominant. In photography, you generally try to avoid hard shadows. In some cases, hard edged shadows can serve to make the right mood: one of tension or roughness. Hard shadows also bring out a surface's texturing and bumps, which is why they are not used when attempting to give a sense of beauty or diffusion to a scene. As already mentioned, hard shadows can be a tremendous distraction when they litter a scene, crossing each other in inopportune places. Let's look at an example. Figure 5.4. 04: Spots with hard edged ray traced shadows. Figure 5.4. 05: Spots with soft buffer shadows. Notice the difference between the images above. With soft shadows, the scene becomes much clearer, as we don't have the hard shadow edges competing with the composition of the rest of the scene. There are a couple of ways to create soft shadows in Blender. The first option is the more physically correct, using time consuming area lamps. They give you a fairly realistic simulation of shadows as they spread and wash out. This is often preferable for close-ups where details like these can make a significant difference. The second option is to use Spot Lamps with soft buffer shadows. You don't get quite the same crisp and realistic effect as with area lights, but this is not always enough of a drawback to matter. Combining soft Spots and Area Lamps is often a preferable solution. Figure 5.4. 06: Hard sunlight. Figure 5.4. 07: Soft diffuse light. Lighting Examples No two images require the same lighting setup, but knowing where to start can sure help. Below are some of the most common types of lighting situations you'll encounter. These are also included on the CD for you to explore in detail. Please don't stick to these examples as though they are law. They are only places to begin, not out-of-the-box lighting solutions. Remember, no two scenes will work out optimally with the same light setup. Outside Exterior settings require you to stick as closely to reality as possible to be credible to the viewer. Experimentation with alternative lighting in these settings shouldn't come at the cost of believability. Clear day Figure 6.1 01: Clear day render. Imagine a clear blue sky with a glaring sun. To obtain lighting like this, you must first understand what illuminates objects in a real world situation, then try to mimic that in Blender. First, you have slightly yellowish sunlight. In Blender, this can be done with, you guessed it, the Sun Lamp. Place it above your scene, pointing downwards at the desired angle (consider whether you want a morning, midday or afternoon feel). Figure 6.1. 02: Sunlight alone. Apart from the sun, you have the blue sky surrounding the scene, illuminating everything with a soft blue cast and turning every bit of shadow blue. This is called sky illumination.