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The Radiance synthetic imaging system

Taken from the Radiance web site http://radsite.lbl.gov/radiance/

Radiance is a suite of programs for the analysis and visualization of lighting in design.

Radiance can be thought of as a renderer as that is the task it is often used for. What makes Radiance different is that it is really a "lighting simulator". So, instead of doing its calculation in raw RGB values and concentrating on fake effects, it uses real units (even if they're still in the RGB colour space) and tries to accurately simulate as much as possible. The feature that really stands out is its ability to accurately simulate diffuse (i.e non-direct) lighting in a scene.

Radiance is able to calculate diffuse lighting like radiosity. However, Radiance is a ray tracer and is thus able to handle non-flat objects such as spheres and cylinders. It determines diffuse light by shooting off many rays from every surface a ray hits. This puts Radiance in the catagory of Monte Carlo simulation since these diffuse rays go off in random directions. Obviously there is a recursion limit (usually only 1 or 2 levels of recursion are needed for most scenes), and there are several other parameters to tune. A scene will seem splochy if the lighting varies alot and too few diffuse rays are spawned.

Radiance avoids being bogged down in ray intersection tests by breaking the scene into an octree data structure as a pre-processor step.
i.e: The scene is bounded by a cube, which is recursively divided and subdivided along the 3 axis' into 8 equal cubes. The recursion ends when a cube contains either no objects or exactly (a part of) one object, or has hit a fixed level or size restriction.
This creates a type of 3D binary tree that makes it very fast and efficient to trace a ray even in very large and complex environments.

--- OPERATION ---

The Radiance is a priestly/prophetic order operated by a self-perpetuating board of Radiant Fathers, all of which were formerly priests/prophets that served the temple.

--- BELIEFS ---

The Radiants believe that their god is the one true god, warring a holy war against all other gods for control of the celestial domain. He is a god of light, holy and cleansing light. The Radiant One honors purity above all else, and purity can only be wrought through fire.

The servants of all other gods must be bled and burned. Ideally they would be brought to the Centrality and burned at the grand pyre, but that is not always practical.

The holy books and writings of doctrine under the institution of all other gods must be blotted out in the blood of those who read them, and burned at the grand pyre.

--- REGALIA ---

The radiant prophets don black sable cloaks of unnaturally heavy weight, are armed with long iron staves, and descend from the temple into the city below to preach canticles of prophetic oracle to the population.

The radiant priests are clad in a slate woolen frock dyed black, and armed with black iron shortswords (iqqoriusundels) which they use for sacrificial purposes.

The Wardens of the Grand Pyre are clad in bohemian leather coats of plates beneath their cloaks, and they are armed with iron swords (iqqoriol) appx. 1.115 ~meter (gor) from tip to the end of the hilt.

--- PROPHETHOOD/PRIESTHOOD ---

The prophets convene every day at dawn to celebrate the coming of their god’s light and every day at night to discuss their individual plans and ambitions and what they accomplished that day. There is a large chamber directly connected to the Centrality which has no official name. The table at which they convene is a huge slab of marble, with pillars of chrome wrought in a circle around the walls of the room. Each prophet will sit with a candle and a book in which they detail events discussed for historical chronicle purposes. The book also contains personal meditations and so forth.

The priests are in charge of maintaining the temple and it’s history. A priestly order of scribes will detail the biographies of all the priests and prophets in the temple library, catalogue the library, and ensure the maintanance/copy of old volumes. A priestly order of temple-keepers will repair and maintain the state of the temple. All other priests will simply reside within the temple and perform religious duties such as replenishing the oil and keeping all the fires lit.
All orders are self-perpetuating unless they are to take a new member by order of the Radiant Fathers, with the exception of wardens, which are only appointed by the Radiant Fathers.

--- WARDENS ---

The temple keeps a company of wardens, former priests/prophets who are appointed warden for performing admirably. They are allowed to decline promotion. There are twenty wardens of the Grand Pyre, and twenty wardens in general service to the temple.
The Wardens of the Grand Pyre are posted in the Centrality in groups of four, one shift per day and one shift per night, different individuals will cycle through shifts.
The wardens in general service to the temple will guard the entrance or escort members of the temple if needed. If they serve faithfully, they will be offered a promotion to a Warden of the Grand Pyre.

Ra"di*ance (?), Ra"di*an*cy (?), n.

The quality of being radiant; brilliancy; effulgence; vivid brightness; as, the radiance of the sun.

Girt with omnipotence, with radiance crowned. Milton.

What radiancy of glory, What light beyond compare ! Neale.

Syn. -- Luster; brilliancy; splendor; glare; glitter.

 

© Webster 1913.

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