I have several CAD files (DWG) that I want converted to Feature Classes within a file GDB. Each feature class will be based on a polyline attribute "LAYER" value, so I have a query filter applied before they get loaded into the GDB.

I think my script (Python 2.7) has a problem with there being no values being written to the ValueTable. Here's the script, followed by the error message - can anyone please help?


# Description: Imports and merges polylines from one CAD workspace into a single feature class

import arcpy 
from arcpy import env

env.workspace = "X:/GEMS_vector_data/DWG_files_sites_floors/0011-test" 
CADgdb = "X:/GEMS_vector_data/DWG_files_sites_floors/0011-test/CADToFeatures.gdb"

# Create a value table that will hold the input feature classes for Merge
vTab = arcpy.ValueTable()

# Step through each dataset in the list
for fd in arcpy.ListDatasets("*", "CAD"):
    LayerName = fd + "_level"
    # Select only the Polyine features for external walls
    arcpy.MakeFeatureLayer_management(fd + "/Polyline", CADgdb + LayerName, "\"Layer\" = 'AR_WALL_EXT'")

# Merge the CAD features into one feature class
MergedFloorPlans =  "X:/GEMS_vector_data/DWG_files_sites_floors/0011-test/CADToFeatures.gdb/Floors01"
arcpy.Merge_management(vTab, MergedFloorPlans)


Error msg

Traceback (most recent call last): File "X:\GEMS_vector_data\DWG_files_sites_floors\0011-test\import_CAD_to_FBDB_01.py", line 26, in arcpy.Merge_management(vTab, MergedFloorPlans) File "D:\Program Files\ArcGIS\Server\arcpy\arcpy\management.py", line 3762, in Merge raise e ExecuteError: Failed to execute. Parameters are not valid. ERROR 000735: Input Datasets: Value is required Failed to execute (Merge).

1 Answer 1


I had the same problem today.It turns out that ESRI sample that you used is wrong. they used

for fd in arcpy.ListDatasets("*", "CAD"):

but "CAD" is wrong, is not a valid feature type for this tool - remove it and the script will work, or use "*.dwg".

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