JReality

Environ Menu ______________________________________________________________ | CM Surveyor | |------------------------------------------------------------| #2 Menus | File Personal Environ Section Fidelity View Help | |--------------|-------------------|-------------------------| | | Sun Position | | | Sun Intensity | | Sky Appearance | | Scene Orientation | --------------------- Purpose: Provide control over the angle and intensity of daytime lighting, including both direct sunlight and ambient light. Usage: To Display Menu: press left mouse button while cursor is over Environ menu bar item. To Select a Menu Item: display the Environ menu, drag cursor over the desired menu item, then release the mouse button. Notes: All Environ menu items are dialog windows.

Sun Position ______________________________________________________________ | CM Surveyor | |------------------------------------------------------------| #2 Menus | File Personal Environ Section Fidelity View Help | |--------------|-------------------|-------------------------| | | Sun Position | | | Sun Intensity | | Sky Appearance | | Scene Orientation | --------------------- ___________________________________________________________________ | Sunlight Dialog | |-----------------------------------------------------------------| | |/\|/\| |/\||/\| |/\||/\|| | |~~|~~| |~~||~~| |~~||~~|| | | | | | || | | || || | | | | | || | | || || |+----------------+| | | +---------+| || | +---------+| || || || 0 deg 0 min || | | | Mar 22 || ||__| | Mar 22 || || || |+----------------+| | | +---------+| ||--| +---------+| || || | Latitude |__|__| Date | || | Hr of Day |__|| || | |--|--| +---------+| || | |--|| || | | | | | 81 || || | | || || | | | | +---------+| || | | || || | | | | Day of Yr |__|| | | || || | | | | |--|| | | ||__|| | |__|__| |__||__| |__||--|| | |\/|\/| |\/||\/| |\/||\/|| | _________ +--+--+ +--++--+ _________+--++--+| | | 18:0 | | 6:0 | | | +-------+ Accept Reset Cancel +-------+ | | Sunset Sunrise | ------------------------------------------------------------------- Purpose: Sets the azimuth and elevation of sunlight illumination by specifying the latitude of scene, the time of year, and time of day. Usage: To Set the Sun Position: Set the scene latitude using the Latitude scrollbars. The left scrollbar sets degrees of latitude and the right sets minutes of latitude. Set the time of year using the Date scrollbars. The left scrollbar sets the month and the right sets the day of the month. There is no provision for leap years (February always has 28 days). The day of the year is displayed because this is the value of relevance to the sun position calculation. Set the time of day using the Hr of Day scrollbars. The left scrollbar sets the hour and the right sets minutes. Click the Accept button. To Restore Previous Sun Position: press Reset instead of Accept after sliding the scrollbars. The scrollbars are returned to the settings of the last Accept. To Dismiss the Sun Posiiton Dialog: press Cancel. Also resets the scrollbars to the last Accept'ed value. Notes: The Sun Position dialog settings have no effect unless lighting is on. The azimuth and elevation of the sun are computed and saved internally for use by the lighting calculation. Azimuth is measured with 0 degrees being due North and positive azimuth counterclockwise. See diagram below. _________________________________________ || North || #5 Top || <-- +Azimuth Y -Azimuth --> || 2D View || | || || West |___ X East || || (sunset) South (sunrise) || __||__________________________________||__ -------------------------------------- -- Top View (Y) Times of sunrise and sunset are computed as an aid to setting the time of day. If the time of day is set to before sunrise or after sunset, direct sunray lighting is disabled. If time of day is set to 30 minutes or less before sunrise or 30 minutes or less after sunset, ambient lighting is set to a progressively reduced value. Beyond 30 minutes, ambient lighting is also disabled, and the scene will appear totally dark with lighting turned on (lamp lighting is not yet implemented). There is no allowance for daylight savings time or other political adjustments. The combination of sun position and scene orientation allows modeling real life situations where both the angle of the sun and the angle of a geometric structure are significant, such as orienting a house on a lot for improved energy efficiency. The default sun position is directly overhead (90 degree elevation), which corresponds to Spring Equinox (Mar 22) at the equator (0 degrees latitude) at 12 noon (12:00 hrs). Accurate sun position calulations are complex, and the Sunlight Dialog implements only the basic equations. While an extensive accuracy check has not been performed, a spot check with sunrise and sunset times from the Naval Observatory for 31 degrees latitude indicates the Sunlight Dialog has a maximum error of about +-20 minutes. This equates to a maximum sun angular error of about 5 degrees in azimuth and 2.5 degrees in elevation.

Sun Intensity ______________________________________________________________ | CM Surveyor | |------------------------------------------------------------| #2 Menus | File Personal Environ Section Fidelity View Help | |--------------|-------------------|-------------------------| | | Sun Position | | | Sun Intensity | | Sky Appearance | | Scene Orientation | --------------------- __________________________________ | Intensity Dialog | |--------------------------------| | |/\| |/\|| | |~~| |~~|| | | | |__|| | | | |--|| |+---------+| | +---------+| || || 0.6 ||__| | 0.85 || || |+---------+|--| +---------+| || | Sunray | | Ambient | || | | | | || | | | | || | |__| |__|| | |\/| |\/|| | +--+ +--+| | Accept Reset Cancel | ---------------------------------- Purpose: Set the intensity of direct sunlight and ambient lighting to simulate daylight reducing effects such as haze, or to simply make the scene look its best when lit. Usage: To Set Direct Sunlight Intensity: adjust the Sunray scrollbar with the mouse. then click Accept. To Set Ambient Light Intensity: adjust the Ambient scrollbar with the mouse. then click Accept. To Restore Intensities: press Reset instead of Accept after sliding the scrollbars. The scrollbars are returned to the settings of the last Accept. To Dismiss the Intensity Dialog: press Cancel. Also resets the scrollbars to the last Accept'ed value. Notes: The Sun Position dialog settings have no effect unless lighting is on. Setting the Sunray value to zero disables direct sunlighting, regardless of other settings. Likewise, setting the Ambient value to zero disables ambient lighting. Because the intensity of each type of daytime lighting is controlled separately, effects such as full direct sunlight with no ambient light (such as might occur in outer space) are possible.

Sky Appearance ______________________________________________________________ | CM Surveyor | |------------------------------------------------------------| #2 Menus | File Personal Environ Section Fidelity View Help | |--------------|-------------------|-------------------------| | | Sun Position | | | Sun Intensity | | Sky Appearance | | Scene Orientation |____________ -------------------| = = = = = =| | * Clear | | o Cloudy | | o Overcast | -------------- Purpose: Set the VR Window background to model a selected sky appearance. Usage: To Set a Clear Sky: click the Clear menu item. To Set a Cloudy Sky: click the Cloudy menu item. To Set an Overcast Sky: click the Overcast menu item. Notes: A Clear sky is modeled by a uniform light blue background color, while an Overscst sky is modeled by a uniform light gray background color. A Cloudy sky is modeled by an image of clouds. The supplied image is a fixed size of 1024x512 pixels. Java3D does _not_ stretch it to fill the background when the Surveyor frame is resized. For monitor resolutions of 1024x728 or smaller, this should present no problem. For larger monitor resolutions, stretching the Surveyor frame to full size can result in a Cloudy background that only partialy fills the VR Window. This can be fixed by using an image editor to expand the size of the "image_cloudySky.jpg" image in the [codebase]/sgdata/image directory, or by substituting a larger cloud image file. When the sun position is set to an Hour of Day that represents night, the VR Window background is automatically turned to black regardless of the Sky Appearance menu setting.

Scene Orientation ______________________________________________________________ | CM Surveyor | |------------------------------------------------------------| #2 Menus | File Personal Environ Section Fidelity View Help | |--------------|-------------------|-------------------------| | | Sun Position | | | Sun Intensity | | Sky Appearance | | Scene Orientation | --------------------- ____________________________ | Scene Orientation | |--------------------------| | |/\| Accept | | |~~| | | | | | |+------------+| | | || 0.0 ||__| Reset | |+------------+|--| | | Orientation | | | | | | | | | | Cancel | | |__| | | |\/| | ---------------------------- Purpose: Allows the scene to be rotated in the plane of the Earth relative to the sun position so that direct sunlight comes from the desired direction. Usage: To Set the Scene Orientation Angle: adjust the Orientation scrollbar to the desired scene azimuth angle (in degrees), then click Accept. To Restore the Previous Orientation: press Reset instead of Accept after sliding the scrollbar. The scrollbar is returned to the last Accept'ed setting. To Dismiss the Scene Orientation Dialog: press Cancel. Also resets the scrollbar to the last Accept'ed value. Notes: The Scene Orientation setting has no effect unless lighting is on. The orientation angle is subtracted from the sun azimuth such that the net effect is the same as rotating the scene relative to North. For example, assume at zero degrees orientation angle we have: sunlight __________________________/_/_/__________ || North / / / || #5 Top || <-- +Azimuth -Azimuth --> || 2D View || ---------- || || / | || || \ scene | || || ---------- || __||__________________________________||__ -------------------------------------- -- Top View (Y) In real life, rotating the scene +90 degrees would result in: sunlight __________________________/_/_/__________ || North / / / || #5 Top || <-- +Azimuth -Azimuth --> || 2D View || ------ || || | | || || | | scene || || | | rotated +90 || || \ / || __||__________________________________||__ -------------------------------------- -- Top View (Y) However, actually rotating the scene geometry is very inefficient, so we rotate the sunlight azimuth instead to achieve the same effect: _________________________________________ || North || #5 Top || <-- +Azimuth -Azimuth --> || 2D View || ---------- || || / | || || \ scene | || || ---------- || __||____________________\_\_\_________||__ -------------------------\-\-\-------- -- Top View (Y) sunlight at +90 orientation The combination of scene orientation and sun position allows modeling real life situations where both the angle of the sun and the orientation angle of a geometric structure are significant, such as orienting a house on a lot for improved energy efficiency.