| Applies To | |||
| Product(s): | MicroStation | ||
| Version(s): | 08.05.00.57 | ||
| Environment: | N\A | ||
| Area: | Visualization | ||
| Subarea: | Lights | ||
| Original Author: | Bentley Technical Support Group | ||
Problem
User is rendering an indoor scene which is lit by both artificial lights and solar light. If Solar is toggled on in the Global Lighting dialog box, the artificial lights don't appear to produce any light. He has tried shooting more particles, but it hasn't helped. He also tried adjusting the Brightness and Contrast sliders, but this doesn't help either.
Product: MicroStation V8 2004 Edition
Version: 08.05.00.57
Area: Visualization
Solution
This is most likely due to the limited dynamic range of computer monitors (and film, for that matter). A scene with both solar and artificial light has a very wide dynamic range, where the direct sunlight is orders of magnitude brighter than the artificial light. While the human eye's fantastic dynamic range has no problem seeing the entire range of intensity, the computer monitor can only display a comparatively small slice of the visible spectrum. Like a piece of film, it can display either the low end of the spectrum, where the artificial light is visible but the scene as a whole is over-exposed, or at the upper end of the spectrum, where the solar light is exposed properly but the lower end is missing.
MicroStation does use a non-linear scaling system when displaying scenes with a high dynamic range, but in some situations this isn't enough. In other situations, the artificial light sources simply don't produce enough light to be seen. Think of a car driving on a bright summer day with its headlights on; the head lights add no perceivable contribution to the scene.
There are a number of things to try to alleviate the situation. Try toggling 'Add Sky Light to all Solar and Distant Lights' on, and increasing the Cloudiness or decreasing the Air Quality (Turbidity ) to decrease the intensity of the sunlight. If you're not concerned about the accuracy of the solution, decrease the dynamic rang e by faking the lighting so that it falls within the monitor's dynamic display range. One way would be to increase the intensity o f the artificial lights. A more common way is to lower the intensity of the Solar light. While the slider only goes down to 0.01, you can use values as low as 0.001. While all light sources will be visible with this setting, the renderings will most likely lack realism.