AcRxObject AcGiDrawable AcHeapOperators AcDbObject AcDbIndex AcDbSpatialIndex
class AcDbSpatialIndex : public AcDbIndex;
dbspindx.h
This class is an index implementation especially for the spatial index.
When using AutoCAD indexes, the INDEXCTL system variable must be set to the appropriate value. For example, INDEXCTL must be either 2 or 3 for the AutoCAD spatial index. See the System Variables section of the AutoCAD Command Reference for information on INDEXCTL.