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Grouping (EN)

 
Примечание по созданию групп объектов, которые и создают те самые простейшие ноды, о которых идет речь в этом разделе.

Копипаста статьи из MaxImmerse.chm (С)
 
Grouping, Triangle/NiTriShape Ratios, and Culling
As with Multi/Sub-Object materials, grouping should be used with care. Grouping decreases the triangle/NiObject ratio. Everything in a scene in Max has a corresponding node (notice the lowercase) in its scene graph. In NetImmerse, that node is called an NiNode. NiNodes and NiTriShapes are two kinds of NiObjects. An NiTriShape is an NiObject that represents a group of triangles while an NiNode is an NiObject that has children and contains transforms. Whenever a collection of objects in Max is grouped, MaxImmerse has to add another NiNode to group them together in NetImmerse. As an example, below is the Max hierarchy for a scene without grouping alongside the NetImmerse scene graph:
When the four Planes are grouped together the two scene graphs become:
Assuming two triangles per plane, grouping has changed the triangle/NiObject ratio from 8/9 in the first case to 8/10 in the second case (i.e. the Group01 NiNode has been added) while the triangle/NiTriShape ratio has remained the same at 8/4. This example is trivial, but indiscriminate use of grouping can have a significant effect on the triangle/NiObject ratio. In general, a high triangle/NiTriShape ratio has better frame-rate performance and a low triangle/NiObject ratio does not. On the other hand, grouping can be useful for efficient culling. If a four-walled room is out of the camera’s view, it is faster to cull the room as a group instead of the four individual walls.