further:
Drawings saved to legacy drawing file formats (2007 DWG format or earlier) do not support objects larger than 256MB. The 2010 DWG format removes this limitation.
The LARGEOBJECTSUPPORT system variable controls the object size limits and the warning messages displayed when a drawing is saved.
If either of the following limits are exceeded, the drawing cannot be saved to a 2007 DWG format or earlier drawing file format until the issues are resolved. Resolve the size limits by breaking the drawing or objects up into several drawings or objects.
Drawing files cannot exceed an internal size limit of 4GB, as measured by the total size of all objects in a drawing when uncompressed. Since a drawing file is normally compressed, the final size of a saved drawing file on disk will vary based on the size and number of objects in a drawing.
Each individual object in a drawing cannot exceed an uncompressed size limit of 256MB. For example, a mesh object, when the drawing is saved and compressed, might be 75MB in size while the same object when uncompressed might be 257MB.
Note When working with a 64-bit release, you can work with large objects and drawings more efficiently. However, the drawing files you create might be too large to open with a 32-bit release version of the same product.
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To Maintain Large Object Compatibility With Legacy Drawing File Formats
Right-click the drawing area and choose Options.
On the Open and Save tab, under the File Save heading, select the Maintain Drawing Size Compatibility check box.
