Qimera Shading Parameters Dialog
How to Start
- Shading Parameters button of Static or Dynamic surface attribute panel
- Default Surface Shading section of Shared Preferences tab in Application Preferences dialog
What it Does
This dialog controls shading parameters for surface generation.
General Description
Dynamic Lighting Toggle
When this option is toggled on the amount of illumination a surface receives is adjusted in a manner that enhances the illumination for relatively flat surfaces and reduces it for mountainous surfaces. This tends to make most surfaces look good with the default settings but at the expense of accurate reported vertical exaggeration and sun altitude angles. This is what Fledermaus version 7 did for illuminating surfaces. If accurate sun elevation and vertical exaggeration values matter to you more the the look of the surface then don't use this option. You can achieve the same or a similar look without the dynamic lighting on but you will generally have the adjust the sun elevation to make it higher in the sky than the default (~63 degrees) and then increase the vertical scale until the desired look is achieved. The amount of elevation and vertical scale will depend on the shape and z-range of the surface.
Lighting Direction
The arrow in this box represents the sun direction, which can be rotated to any azimuth from 0 to 360 degrees by clicking and dragging the left mouse button inside the box. The sphere in the middle of the diagram displays the current direction and length of the cast shadows. Dragging the slider located on the right side of the Shadow Direction box adjusts the sun altitude from 0 to 90 degrees, where 0 degrees indicates the sun would be at the horizon and 90 degrees would indicate the sun would be directly overhead. In the example shown in the figure the light is coming from the North West (upper left) and the sun is at 45 degrees in the sky (halfway). On the right of the area, both the azimuth and altitude can be edited directly.
The rest of the parameters are controlled via the following slider controls.
Ambient
This slider controls the amount of ambient or background light in the lighting model. It primarily affects the amount of light that appears in cast shadows. High ambient light makes the entire image brighter and the shadows less distinct.
Specular
This slider controls the amount of glossy highlight that appears. High specular makes the surface appear to be very glossy. Low specular will provide a matte finish.
Soft Shadows
This slider controls how sharp or soft the shadow edges are.
Vertical Scale
The height of the surface can be artificially increased or decreased to change the shadow length. Occasionally this is useful to enhance a low relief surface or reduce a very high relief surface. It is usually better to use the Shadow Direction/Length box to configure and adjust the shadow length.
All of the sliders work in a standard way. To change the position of the slider select and drag it using the left mouse button. To go directly to a specific part of the slider bar click the middle mouse button.
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