The program indexes objects in a region by recording their positions in space. The
result is called a spatial index. The spatial index is tree structured and has branching nodes to which objects are
attached. The index has two major branches. The paper space branch is called a quad-tree
and treats objects as 2D. The model space branch is called an oct-tree and treats
objects as either 2D or 3D. The model space branch can also be changed to a quad-tree
when you are working on 2D drawings.

TREESTAT displays information about each branch. The most important information is
in the first two lines of the report—number of nodes, number of objects, maximum depth
of the branch, and average number of objects per node.

If REDRAW and object selection are very slow, you can improve their performance. For
example, if there are 50 megabytes of memory available and the current drawing has
۵۰,۰۰۰ objects with only 1,000 nodes in the index tree, increase the TREEDEPTH value
to improve performance.

Each node consumes about 80 bytes of memory. The fewer objects per node of the oct-tree,
the better the performance.