Essential Blender- P21

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Essential Blender- P21

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Essential Blender- P21:You may copy and distribute exact replicas of the OpenContent (OC) as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and give any other recipients of the OC a copy of this License along with the OC.

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  1. 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.
  2. 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,
  3. 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.
  4. 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.
  5. Figure 5.4. 04: Spots with hard edged ray traced shadows.
  6. 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.
  7. Figure 5.4. 06: Hard sunlight.
  8. 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.
  9. 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).
  10. 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.
  11. Figure 6.1. 03: Sky illumination alone. To properly obtain that effect in Blender, you need to apply some AO to the scene, and add a sky blue hemi light for the correct color in the shadows. There are alternatives to AO, like setting up a couple of blue lights around the object, but they struggle to give the nice all-round soft shadows that AO delivers. The circle light method described earlier can perhaps give a good enough effect, and is worth a try.
  12. Figure 6.1. 04: Sun light on one side of a tower, with the blue cast from sky illumination on the other side. Cloudy day
  13. Figure 6.1. 05: Cloudy day render. A day with clouds drifting around, blocking the sun every so often. The setup for this is much like the clear day setup. The only differences are that the sunlight is lower in intensity, depending on how much cloud cover there is at the time of the render, and the sky illumination color is toned more toward gray. The energy of the Sun Lamp can be slowly animated to produce the feeling of the sun moving into areas of greater and lesser cloud coverage. Overcast day
  14. Figure 6.1. 06: Overcast day render. We've all experienced one of those days with completely dull, overcast weather. In those cases, there isn't any direct sun light at all, and the only natural light source left is the gray glow coming from clouds. Ambient Occlusion with little to no key light source, or circle lighting, will achieve this effect.
  15. Figure 6.1. 07: On overcast days, shadows are diffuse. Sunset/Sunrise
  16. Figure 6.1. 08 Sunset/sunrise render. Staging a scene at sunset or sunrise can add a lot of mood. Set a sun lamp at a very low angle and give it an orange/red color. Make the sky illumination color (from Hemi Lamps and AO using Sky Color) a mix between blue and red. A wide range of colors can actually be applied to a situation like this. From yellows to oranges, onto reds and sometimes even pinks. Shadow colors from the Hemi Lamps can be dark blues and purples. It's a very beautiful time of the day that seems to be completely new and different each time you see it, so there is more than enough variation to play around with. Clear night
  17. Figure 6.1. 09: Clear night render. This render represents a night with no clouds, and the moon shining brightly. Moon light can be cast by a Sun Lamp with a white or slightly blue color. Apart from that, low energy blue/gray sky illumination is needed as well. When lighting a night scene, though, focus on keeping everything visible. Instead of turning down lamp energy so low that you cannot see your subjects, tint the light blue and use detailed rim lighting to show forms. Overcast night
  18. Figure 6.1. 10: Overcast night render. Like a clear night, except you remove the moon and make the sky illumination even grayer. This setup is the hardest to get to work, as it doesn't look very natural if it's bright enough to be able to see anything clearly. In reality, these lighting conditions (overcast night) mean that there is almost no discernible light to begin with, so no matter what you do, it won't look natural. Interiors In interior settings you encounter a new type of light: artificial. Light bulbs can be divided into two types: incandescent and fluorescent. Although the difference in the light they cast has become increasingly small in the last few years due to new technologies, most people can still tell them apart at a glance. Incandescent lights
  19. Figure 6.2. 01: A render with incandescent lights hints. Incandescent light is the kind generated by typical filament bulbs or halogen lamps. Depending on the bulb, it can have anywhere from a warm yellow/orange to white (typically for newer types). This form of light is widely used in homes. In 3D you set up lights where you would place them in real life: on walls and ceilings. A little AO with an orange cast to it (maybe done with Hemi Lamps), can be used to fake the way that light bounces around in the room.
  20. Figure 6.2. 02: Light sources in homes are mostly incandescent. Fluorescent lights
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