Atmosphere Parameters
The parameters in this rollout control the Sky rendering method, the rendering quality and various physical properties.
Rendering
Steps - This value represents the step size in world units of integration path. In other words, to calculate the pixel color, DreamScape has to perform numerous steps though the atmosphere. With the Steps spinner, you can choose how big each step will be.
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Steps = 5 |
Steps = 10 |
Steps = 20 |
A bigger number will produce a better image (especially for pictures with small Height Scale parameters set for Haze or Sky). The smallest step value is 5; the Default is 10. Steps above 20 will have no visible effect.
Multiple Sc - If you enable the Multiple Scattering checkbox, this option it will instruct DreamScape to use multiple sunlight scattering rays throughout the atmosphere. Generally, this gives you a brighter sky as shown below.
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Multiple Sc. = 0.01 |
Multiple Sc. = 0.1 |
Multiple Sc. = 0.2 |
Realism - This slider lets you determine which Dreamscape atmospheric algorithm will be used to render the sky. As you go from left to right, you will get more realism as the cost of rendering speed.
Flat Earth - A flat model of the Sun and sky behavior on the scene. This model assumes that the ground is calculated as an infinite plane (not a sphere which is more appropriate for a planet), and is good if you don't need lots of realism.
Real Earth - Real Earth model of the Sun and sky behavior in the scene. The Earth is calculated properly as a sphere, which enables rendering of great sunsets. It also gives you more realistic cloud fading behind the horizon.
Reddening - When you choose an Earth model that includes reddening, it will attenuate the light intensity in the atmosphere that causes red sunsets. While it's effect on your DreamScape Sky is most notable during a sunrise or sunset, it does affect the look of the sky even at midday.
Sky
Density - The density of the atmosphere actually represents how thick the air is, or how many particles there are in the unit volume of the atmosphere. This spinner tells DreamScape how to calculate the proper lighting for the Sky. Higher values will produce a thicker atmosphere.
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Density = 4.0 |
Density = 9.0 |
Density = 20.0 |
An extremely low density setting (below 1) will produce images of alien worlds where there are only small amounts of gases and particles in the atmosphere (lower atmosphere density can be found on high mountain peaks on Earth, of course). Values around 5 will produce an Earth-like clean atmosphere with a barely visible horizon reddening on the sunset. If you want to create a beautiful red sunset, then you should use values around 9. Extreme values will produce the effects of a very dense atmosphere, an extremely red sunset and a brownish horizon even if the Sun is high.
Glow - We see the Sun glow inside our atmosphere because the Sunlight scatters on small particles and air molecules. On a very high mountain, the Sun's glow is much weaker than in a large city, due to the thinner and cleaner air. Higher values for the Glow spinner will produce a larger glow area around the Sun.
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Glow = 1.0 |
Glow = 2.0 |
Glow = 5.0 |
Outside of our atmosphere, where there are almost no particles, Sun glow does not exist.
You can use this parameter (along with the Glow Sharpness spinner) to simulate how clean the atmosphere is.
H. Scale - The Height Scale spinner's value represents the atmosphere height at which the air density falls to approximate one-third of the ground density. In the real world, it is well known that the atmospheric density of our world decreases with the distance from the Earth surface by exponential law (for you tech geeks, mathematically the formula is: D(h)=D0*exp(-h/H_scale)).
Higher values will stretch the air density further up throughout the Earth's atmosphere.
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H. Scale = 3000 |
H. Scale = 7994 |
H. Scale = 20,000 |
Color - You can use this option to determine the general color of the sky. Left-click the color swatch as you would any other color swatch inside of 3ds Max and it will open the Color Selector menu. This color does not define the sky color directly, but defines the atmosphere scattering color.
Glow Sharpness - This option lets you choose the level of the Sun's glow sharpness. With higher Glow Sharpness values, the glow surrounding the Sun will have sharper edges.
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Sharp = 0.88 |
Sharp = 0.91 |
Sharp = 0.99 |
Haze
Density - This spinner controls how thick the haze layer will be within your atmosphere. With higher density values, the scene will look dimmer. (Note that you can compensate for this with the Haze Brightness parameter.)
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Density = 0.1 |
Density = 1.0 |
Density = 2.5 |
H. Scale - The Height Scale spinner determines the height at which the Haze density falls to approximately one-third of the ground density.
Bigger values will stretch the haze density further up throughout the Earth's atmosphere.
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H. Scale = 1200 |
H. Scale = 5000 |
H. Scale = 10,000 |
Color - You can use this option to determine the general color of the haze layer. Left-click the color swatch as you would any other color swatch inside of 3ds Max and it will open the Color Selector menu.
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White Haze Color |
Blue Haze Color |
Red Haze Color |
Brightness - The Brightness spinner controls the overall brightness of the haze layer. With higher values, the haze color will become brighter. This spinner works hand in hand with the Haze Density spinner to create a pollution or haze layer in your atmospheres, and you should be sure to increase this parameter if you increase the Haze Density to get the same overall brightness to your Sky as shown below.
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Brightness = 0.1 Density = 1.0 |
Brightness = 1.0 Density = 1.0 |
Brightness = 2.0 Density = 1.0 |
Rainbow
Rainbow - Activate the Rainbow checkbox to allow the creation of a rainbow with the desired width and brightness in your atmosphere.
Width - This spinner determines the overall width or thickness of the rainbow itself. Larger values will produce wider rainbows.
Brightness - This spinner determines the intensity or visibility of the rainbow. Higher values will produce a more intense rainbow effect.
Note: Rainbows are only visible when the Sun is behind the viewer and their position is determined by the angle of the Sun light to the camera.