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Tip# 3149 By Harry Katchadoorian On 22-Feb-2009
Rated By 1 users
Categories : Draw Order
Software type : AutoCAD
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Use these alternate settings for the way AutoCAD processes spatial data.

Harry Katchadoorian sent us a tip discussing alternate settings for the way AutoCAD processes spatial data.

I have been using AutoCAD since version 14 to create GIS maps for the city of Fontana.  I have found a very useful, but simple, command that allows us to take a layered drawing and reorder the layers using the Draw Order icons. This command is TREEDEPTH and is set to 3020 by default.  I have found that a value of 10 seems to work for all of our drawings.  Without changing this setting, the Draw Order functionality just doesn’t work.  I’m now using the AutoCAD Map 3D 2009 and everything seems to work the same as in 2007.  Sorry, I was a bit slow and missed 2008.

Notes from Cadalyst Tip Patrol:  Interesting tip.  Most of us are not concerned about how AutoCAD, AutoCAD MAP3D, or any of its verticals process referenced files and the draworder of the objects within them.  Sometimes however, we need to control these issues in a way that is different from the default settings.  TREEDEPTH is a variable that controls the way AutoCAD indexes drawing objects spatially.  If TREEDEPTH is set to zero, then spatial indexing is turned off, and AutoCAD will process the objects in one giant database.  You lose performance.  If it is set to a value greater than zero, then spatial indexing will be turned on.  You can use a number that is up to five digits long, the first three refer to objects in model space, and the last two refer to objects in paper space.  If TREEDEPTH is set to a value less than zero, then spatial indexing treats model space objects as if there is no Z value. 

This obviously works best in 2D drawings.  So, this means that our tipster has set his spatial indexing to a value that will only process model space objects.  Spatial Indexing performance boost comes when xrefing drawings and using draw order.  The setting helps AutoCAD to know what, where, and when to process data.  The more digits and the higher the number, the more indexes AutoCAD will create.  Look at it this way: a setting of zero means you have one cabinet shelf to set all of your objects in.  It can be difficult to find what you need.  A negative setting means you only spread out with more cabinets horizontally.  A positive number means you now have columns and rows of cabinets to sort everything in.  It also organizes those rows and columns according to paper space and model space, if you have enough digits.
Tested in AutoCAD 2009



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