DEPRECATED. This shader is unsupported, but it may still get installed with Softimage to provide compatibility with older scenes that
use it. It is recommended that you replace unsupported shaders in your scenes with equivalent shaders from the current Softimage
shader library.
| Global | Atmosphere | Ground | Cloud | Star | Moon | Sun
Environment (Legacy)
Output: Color (RGB) value
Acts as a planet-atmosphere simulator. It uses advanced numerical techniques to simulate the scattering that light undergoes
when traveling through an atmosphere. This makes it possible to simulate both a view of a planet from outer space and an outside
view of the planet's surface.
NoteNo render tree connections are possible with this shader.
Global
Global Parameters
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Determines the position of the point of view relative to the planet's center. The direction is given as Inclination and Azimuth.
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The default value is 1.8 m above the surface (about where a tall person's eyes are). There's an important difference between the viewpoint in the shader and the real viewpoint in the scene. This viewpoint (the
shader's) determines how the environment shader looks, and the position of the camera within the scene has no effect on that.
You can place the viewpoint outside the atmosphere, resulting in an extraplanetary view, by giving an altitude of, e.g., 100
km and using the default parameters, pointing the camera downward.
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The default value is 6 000 000 m (approximately equal to the Earth's radius).
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Controls the overall brightness of the image. With the checkbox unchecked, this is an overall scaling factor.
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Causes the brightness of the environment to be scaled in such a way that the ground directly under the viewpoint has the illumination
of that specified in "view gain." This is very useful for daylight scenes, where you might put a ground map on and you want
it to be properly illuminated.
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Atmosphere
Atmosphere Parameters
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Scale thickness of the atmosphere. The default value is 7400 m (the thickness of the Earth's atmosphere if its density were
uniform).
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Scale thickness of the atmosphere. Modifying it affects the color of the sky and the sunset.
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A smaller sphere of dust is a part of the atmosphere. Defines the height of the dust.
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The density of the dust. The dust makes a gray-colored haze appear. It will make a very effective halo around the sun as well.
You may want to set this to 0 for Arctic clarity of the air. When it is set high, the sun will no longer be discernible from
the glare.
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The shader works by integrating the air density over a number of invisible sample spheres in the atmosphere. This controls
their number. High values (like 20) give more accurate results but take longer rendering. Low values can be very adequate,
but it depends on the view position. Keep it as low as you can until you are satisfied with the results.
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Ground
Ground Parameters
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Useful for extraplanetary scenes, where you can map a geographical map on the planet using the traditional spherical mapping
with two pinch points at the poles. When this mapping type is selected, the scaling is no longer in kilometers and a scaling
of 1 means that the map will stretch once around the planet.
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Similar to cloud mapping and is useful for ground scenes where you could place a map on the ground.
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Transformations
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The scaling of the map. In lollipop mode, it states how many kilometers each instance of the map should stretch. In spherical
mode, it determines how often the map wraps around the planet.
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A rotation of the map
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The translation of the map. The same difference between the modes applies here as with the scale parameter.
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Cloud
Cloud Parameters
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The color of the clouds. Mars has red ones, we like white ones (unless you live in the UK, where they're "gray").
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Creates a more turbulent-looking cloud fractal.
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Places the cloud plane in the atmosphere model; 500 m is about right.
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Defines the cloud fractal's amplitude.
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The fractal ratio; a value of 0.707 works well.
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Clouds are soft so few iterations are necessary.
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This is the center (expected value) of the fractal. 0 = no cloud; 1 = full cloud. This parameter is really a balance control
between the two extremes and works with the Amplitude in placing the fractal in the 0..1 domain.
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When on, the clouds become animatable with the time parameter.
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Only on once you select the Animate option. Defines the speed of the animation.
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Transformations
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The clouds are placed on the planet using a lollipop mapping. This means that there will be stretching and a seam at the South
pole (negative Y direction). Scaling is in kilometers for convenience, so that a scaling of 1 will give the clouds largest
features 1-km diameter.
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Rotates the fractal; can be useful for eliminating visual artifacts due to repetitiveness in the fractal.
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Offsets the cloud fractal; can be animated to produce a wind effect.
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Star
Star Parameters
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Defines how much of the sky is occupied with stars.
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A bias on the random brightness distribution.
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Scales the brightness of the stars. Sometimes they are too faint and have to be scaled to become visible.
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The color saturation of the stars. They have random colors which can be made visible by increasing the saturation.
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Controls how much the brightness varies with time.
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The time with which the star's brightness varies.
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Transformations
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A scaling factor for the stars.
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Rotates the stars about the azimuth.
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An offset factor for the stars.
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Moon
Moon Parameters
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The color of the moon. This is really the diffuse reflectivity of the moon, which is modeled as a ball. Our moon is really
a rather dark object that only appears bright at night because the sun is so much brighter than the night.
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The size of the moon in degrees. From Earth, the sun and the moon look roughly the same size.
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Makes a halo around the moon. Good for simulating a frosty night.
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The deviation from vertical of the moon's center.
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The azimuth direction of the moon.
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Sun
Sun Parameters
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The color of the sun. Our sun is very close to white and that is a useful approximation. However, there is nothing stopping
you from making it green. This, of course, will make the whole scene green.
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A scaling factor of the sun's color. Because the sun is vastly more luminous than any other celestial body, you must be able
to control its color with ease and have it powerful at the same time. The default of 10 is very conservative, relative to
the real world.
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Attenuates the apparent brightness of the sun when it is visible in the shader. The sun itself is usually much brighter than
any other object in the scene. If you want it to appear dimmer, try setting the attenuation to 0.5 - 0.99 when creating a
sunset scene; be careful, though, if you have a high dust density, because the brightness of the scattered light of the dust
will quickly swamp the sun. It may be better simply to scale the scene's overall brightness for the sunset effect.
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The size of the sun disk in degrees. The real sun is very small, so the default value of 5 is slightly exaggerated.
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Makes it possible to make the edges of the sun appear more fuzzy if the dust-produced halo is not sufficient.
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Defines how many degrees from the vertical the sun's center is located.
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Positions the sun in the X-Z plane. 0 is in the X direction; 90 is in the positive Z direction.
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