Union 3D (3D Analyst)
Summary
Merges closed, overlapping multipatch features from an input feature class.
Illustration
Usage
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Closed multipatch geometry is required for this analysis. The Is Closed 3D tool can be used to determine if a multipatch feature class contains closed features, and the Enclose Multipatch tool can be used to eliminate gaps in multipatch features.
Multipatch features encompassing overlapping volumes are combined by intersecting the triangles and rings that constitute the shells of the features and removing redundant interior portions. This process occurs iteratively until all multipatch features in the feature class have been processed.
A grouping field can be used to identify features to be unioned, such as when the multipatches represent building parts in a city where multiple features represent one building. This can significantly improve performance by reducing the number of times the tool must iterate through the dataset. Rather than comparing a feature against all features, it is only compared against those that participate in its group.
When optimization is enabled, the tool attempts to automatically subset the features into groups by analyzing the bounding box for each feature. Disabling optimization can increase the tool's performance if a grouping field has been specified. Optimization can also be disabled in the absence of a grouping field if the desired output is to union all overlapping features into a single multipatch.
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Use caution when deciding how many features to aggregate, as very large and complex features may be created in the output feature class which may exhibit poor display performance.
A warning stating that the resulting feature is not simple and could not be created is raised if two or more multipatch features share only an edge or a vertex. The same message is returned if a group contains multipatches that share no volume or space.
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An optional table can be created to identify the attributes of the source features that were unioned to create each unioned output.
Note:A relationship between the table and the output feature class can be established to query the attributes associated with the source features. Please see Relating the attributes in one table to another for more information.
This tool is a 3D set operator that provides analytical functions on 3D features. See Working with 3D set operators for more information on what set operators are and how to use them.
Syntax
| Parameter | Explanation | Data Type |
in_feature_class |
The closed multipatch features to be intersected and aggregated. | Feature Layer |
group_field (Optional) |
The field used to identify the features that should be grouped together. | Field |
out_feature_class |
The output multipatch feature class that will store the aggregated features. | Feature Class |
out_table (Optional) |
A many-to-one table representing the relationship between input features and their aggregated counterparts. | Table |
disable_optimization (Optional) |
Specifies whether optimization will automatically take place or is disabled:
| Boolean |
output_all (Optional) |
Determines if the output feature class contains all features or only the overlapping ones that were unioned.
| Boolean |
Code Sample
The following sample demonstrates the use of this tool in the Python window:
import arcpy
from arcpy import env
arcpy.CheckOutExtension('3D')
env.workspace = 'C:/data'
arcpy.Union3D_3d('multipatch.shp', 'union_output.shp', 'GROUP_FIELD',
'DISABLE', 'ENABLE', 'UnionTable.dbf')
The following sample demonstrates the use of this tool in a stand-alone Python script:
'''****************************************************************************
Name: Union3D Example
Description: This script demonstrates how to use the
Union3D tool.
****************************************************************************'''
# Import system modules
import arcpy
import exceptions, sys, traceback
from arcpy import env
try:
arcpy.CheckOutExtension('3D')
# Set environment settings
env.workspace = 'C:/data'
# Set Local Variables
inMP = "multipatch.shp"
# Ensure output multipatch has a unique name
outMP = arcpy.CreateUniqueName("union_output.shp")
outTbl = arcpy.CreateUniqueName("UnionTable.dbf")
GroupField = "Type"
optimize = "DISABLE"
solids = "ENABLE"
#Execute Union3D
arcpy.ddd.Union3D(inMP, outMP, GroupField, optimize, solids, outTbl)
arcpy.CheckInExtension('3D')
except arcpy.ExecuteError:
print arcpy.GetMessages()
except:
# Get the traceback object
tb = sys.exc_info()[2]
tbinfo = traceback.format_tb(tb)[0]
# Concatenate error information into message string
pymsg = 'PYTHON ERRORS:\nTraceback info:\n{0}\nError Info:\n{1}'\
.format(tbinfo, str(sys.exc_info()[1]))
msgs = 'ArcPy ERRORS:\n {0}\n'.format(arcpy.GetMessages(2))
# Return python error messages for script tool or Python Window
arcpy.AddError(pymsg)
arcpy.AddError(msgs)