13 - 4   Three-dimensional Light Source

The light source is a point of light infinitely far from the drawing area. You can open the Light Source dialog (shown below) by selecting the button () next to Lighting effect toggle the Plot sidebar, or by selecting "Light Source" from the Plot menu.

The Light Source dialog has the following options:

• Intensity (%) - Controls the amount of lighting effect produced by the directional light source. An intensity of 100 produces the maximum contrast between lit and unlit areas, and fully lit areas use the full surface color. Lesser values produce less contrast between lit and unlit areas, and fully lit areas use darker colors. An intensity of zero means the light source produces no contrast between lit and unlit areas, and all areas are black.

• Background Light (%) - Controls the amount of lighting effect applied to all objects regardless of the light source position. A background light of zero means that areas unlit by the directional light source receive no lighting at all and are entirely black, while areas lit by the directional light source get only the effect of that light. Larger values produce more lighting effect in areas not lit by the directional light source, making these areas show some of the surface color. A background light of 100 means that all areas are lit by the maximum amount, and areas unlit by the directional light source use the full surface color

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• Surface Color Contrast (%) - Controls the contrast of the color of the light source shaded surfaces before applying lighting effects. A surface color contrast of 100 means that light source shaded surfaces use the full surface color for applying lighting effects. Lesser values mean that the surface color is blended with progressively more white, making light source shaded surface colors lighter. A surface color contrast of zero means that colors are pure white before applying lighting effects (the plot will only be shades of gray).

• Include Specular Highlights - Turns on/off specular highlight for all light-source shaded objects in the plot, adding the semblance of reflected light to 3D shaded or flooded objects.

• Intensity (%) - Controls intensity of specular highlights (that is, the amount of reflected light, which controls the amount of whiteness at the peak of the highlight).

• Shininess - Controls shininess of specular highlight (that is, roughly the size and spread of specular highlight).

• Lighting Optimizations - Some combinations of lighting type and plot style may result in very slow redrawing of plots. Tecplot 360 EX provides lighting optimizations to avoid such conditions and instead draws a similar, but less computationally-intensive plot. These optimizations are on by default. Turn them off if you need to see the exact effects you have specified. You may want to turn off the graphics cache before turning off those optimizations for plots with large amounts of data. (See “Graphics Cache” on page 450 for information on the graphics cache.)

13 - 4.1   Moving the Light Source

You may move the light source interactively by clicking the  sun button next to the lighting effect toggle in the Plot sidebar. With the light source tool active, click or drag in the workspace to position the light source in 3D space. Choose another tool from the toolbar or sidebar to exit this mode.