Faking blury Refractions using Reflections
Like I mentioned in the reflection level map section, we only want the leaf to reflect its environment, in such a way that it will look as the leaf is partially see trough but we don't want our leaf to reflect other objects in our scene in this case, like I mentioned before, a leaf's reflections and what you see trough it would have a blur to them because light would get distorted as it passes trough and reflects from the leaf therefore making things you see trough it and are reflected by it look blurry. The point is that raytrace reflections don't have the ability to make blurry reflections or refractions, so the way to get around this is by using a blurry environment/reflection maps. What you would do is render everything that is
behind the leaf and use that render as the leaf's environment and the render environment. Here's a render with en environment with some spheres set up as the leaf's environment map with a blur applied to it. As you can see in this render, the spheres that you see trough the leaf are more believable because of that slight blur.
As we already know, no objects reflect at the same amount throughout its surface in the same way no object has perfect reflections, all reflections have a slight blur to them, even the reflection of a chrome metal, the only thing that would have perfect reflections is a "perfectly clean" mirror, if that mirror was touched by a hand or got slightly wet witch in hand collected some dirt, those areas would have duller reflections than the rest, what this mans is that raytrace reflections would only be accurate when applied to a perfectly clean mirror doe to the inability to blur reflections, therefore making reflection mapping more essential. If your 3d package has the ability to blur raytrace reflections than you should defiantly put it into practice but like faking translucency, faking more accurate reflections is also an essential skill that you must master especially if you consider being a texture artist for a production house since often times this type of things are faked using maps in order to save render time.
So under the raytrace controls rollout uncheck "raytrace reflections" and "raytrace refractions" under raytrace enable, apply the same map you would like to use as the background as your environment map, feel free to use any outdoor environment you might desire, under the coordinates rollout give this map a blur value of about 30 and change the mapping type to "screen" because we want to make the leaf appear to be see trough therefore the leaf's reflection environment has to have the same position and resolution as the render environment background.
Click on the go to parent button to go to the leaf shader's base level, apply a falloff map to the reflection channel,
change it's falloff type to "fresnel", uncheck "override material IOR" and apply our reflection level map to the second slot of the falloff map (slot with a default color of white). Click the go to parent button again and under the "raytrace basic parameters" give index of refl (refl short for reflection) a value of 4. to clear things up a bit, fresnel is a real world effect that causes areas that are further away from the viewer appear to be more reflective than areas that are closer to the viewer, the Index of reflection parameter controls the amount of between the reflection amount of the faces that point directly at the camera and the faces that point away from the camera, the higher the IOR the more the object would appear
to reflect and the smaller the difference between the reflections amount of the faces pointing toward and away from
the camera. An IOR of 4 seemed right in this case because we want our leaf to take some of the color from its environment but not enough to make it look as if the leaf was composed of thin plastic and that finishes off this section.
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