2011

Table Of Contents
To turn on demand loading
1 Click Tools menu Options.
2 In the Options dialog box, Open and Save tab, under External References,
select Disabled, Enabled, or Enabled with Copy.
3 Click OK.
Quick Reference
Commands
EXTERNALREFERENCES
Opens the External References palette.
System Variables
INDEXCTL
Controls whether layer and spatial indexes are created and saved in drawing
files.
XLOADCTL
Turns xref demand-loading on and off, and controls whether it opens the
referenced drawing or a copy.
Work with Layer and Spatial Indexes
To receive the maximum benefit of demand loading, it is recommended that
you save any drawings that are used as xrefs with layer and spatial indexes.
A layer index is a list showing which objects are on which layers. This list is
used when the program is referencing the drawing in conjunction with demand
loading to determine which objects need to be read in and displayed. Objects
on frozen layers in a referenced drawing are not read in if the referenced
drawing has a layer index and is being demand loaded.
The spatial index organizes objects based on their location in 3D space. This
organization is used to efficiently determine which objects need to be read in
when the drawing is being demand loaded and clipped as an xref. If demand
loading is turned on, and the drawing is attached as an xref and clipped, the
program uses the spatial index in the externally referenced drawing to
1712 | Chapter 35 Reference Other Drawing Files