9

Quadtree 999
additional markers for the top, bottom, and middle
of the two props. If these tracks are detected,
character studio createsa3dsMaxdummyobject.
Thelengthofthepropistheaveragedistance
between the top and bottom prop m arker during
animation.Thepropwillbeorientedintheplane
of the three prop markers, and its origin w ill be at
the bottom prop m arker.
Quadt ree
Aquadtreeisadatastructureusedtocalculate
ray-traced shadows (page 3–1000).
Thequadtreerepresentsthescenefromthepoint
of view of the ligh t. The root node of the quadtree
lists al l objects that are visible in that view. If too
many objects are visible, the node generates four
othernodes,eachrepresentingaquarterofthe
view, each with a list of objects in that portion.
This process continues adaptively, until each
nodehasonlyasmallnumberofobjects,orthe
quadtree’s depth limit (which can be set for each
light) is reached.
Each shadow-casting light ray needs to test
intersection with the objects in only one of the
leaf nodes of the quadtree. This helps speed up
the ray-tracing process. In general, increasing
the maximum quadtree depth can speed up
ray-tracing at a cost of memory.
The maximum size of a quadtree is the square of
two to t he power of the maximum quadtree depth.
At a depth of 7, the largest quadtree has 128 x 128
leaf nodes; at a depth of 10, the largest quadtree
has a size of 1028 x 1028 leaf nodes, and so on.
(On the other hand, because each successi ve node
contains fewer objects, the size of a no de’s record
decreases the deeper it is in the tree.)
Note: An omni light can generate up to ten
quadtrees, so omni lights that cast ray-traced
shadows use more memory at render time than
spotlights do.
Queue M onitor
The Queue Monitor is a standalone
network-administration tool that provides
a user interface to monitor and control network
rendering.
The Queue Monitor can connect to any computer
to which you ha v e network access with the
appropriate security perm issions, and a Network
Manager r unning on it. You can install the Queue
Monitor separately. It will function correctly on
any Intel-based computer running Windows NT
with appropriate TCP/IP networking services,
including over the Internet. In other words, you
can monitor and control network rendering
services from any computer connected to the
Internet, in addition to using the Internet as a
wide-area backbone for a network rendering farm.
Radiosity
A technique to calculate indirect light to illuminate
a s cene. Radiosity calculates the i nterreflections of
diffuselightamongallthesurfacesinyourscene.
The result is the radiosity solution (page 3–999).
See Modeling Global Illumination with Radiosity
(page 3–51).
R a dios it y S oluti on
The calculation of the radiosity (page 3–999) effect
in a scene. You compute the radiosity solution as a
separate step from rendering. Once the solution is
computed, it can b e used for multiple renderings.
See Modeling Global Illumination with Radiosity
(page 3–51).