Get a layer from .dxf file and copy that layer to new file

Question

I have tried the following code which can be found here, my objective is to take out one layer from a .dxf file, and the copy to a new file only with that information. On the link where I found the code, the made the following code, but I do not understand why I have an error. I tried to change the layer name, but it didn't work.

from shutil import copyfile
import ezdxf

ORIGINAL_FILE = 'test.dxf'
FILE_COPY = 'test2.dxf'

KEEP_LAYERS = {'Layer1', 'Layer2', 'AndSoOn...'}
KEEP_LAYERS_LOWER = {layer.lower() for layer in KEEP_LAYERS}

# copy original DXF file
copyfile(ORIGINAL_FILE, FILE_COPY)

dwg = ezdxf.readfile(FILE_COPY)
msp = dwg.modelspace()
# AutoCAD treats layer names case insensitive: 'Test' == 'TEST'
# but this is maybe not true for all CAD applications.
# And NEVER delete entities from a collection while iterating.
delete_entities = [entity for entity in msp if entity.dxf.layer.lower() not in KEEP_LAYERS_LOWER]

for entity in delete_entities:
    msp.unlink_entity(entity)
   
dwg.save()

My case is very simple and similar to that code, but I get the following error:

    raise const.DXFAttributeError(

DXFAttributeError: Invalid DXF attribute "layer" for entity MPOLYGON

I didn't found any bibliography tied to that error there is not too much information about this library error on the site.

Answer 1

MPOLYGON is not documented in the DXF reference and is therefore only preserved as DXFTagStorage and has no layer attribute.

Entities without a layer attribute will be deleted:

delete_entities = [
     e for e in msp 
     if not e.dxf.is_supported('layer') or e.dxf.layer.lower() not in KEEP_LAYERS_LOWER
]

Edit: unlink for unsupported entities will work in v0.16.2, until then destroy the entities:

for e in msp:
    if e.dxf.is_supported('layer') and e.dxf.layer.lower() in KEEP_LAYERS_LOWER:
        continue
    e.destroy()

  

Maybe you can post your DXF file (zipped) to see what a MPOLYGON should be, I guess it is a synonym for an already supported DXF type.

Edit: MPOLYGON seems to be an AutoCAD Map specific entity.