How to merge multiple DXF files and assign each file a new layer

[easyw]

Hi @mozman
is it possible to merge different dxf files like in this query https://stackoverflow.com/questions/58722235/python-module-to-merge-dxf-files but assigning the entities of each file to a different layer?
i.e. file1 to edge layer, file2 to silks layer etc., everything in the same dxf merged file

thanks in advance
Maurice

[mozman]

You always have to think like an engineer and combine the tools you have.

Fortunately, the toolbox has grown since the stackoverflow.com post and a bounding box calculation is now also available so I can show you how to merge and move the imported elements and reassign them to a new layer.

This is the content of the base.dxf:

The result of merged.dxf:

This solution is limited by the features of the Importer add-on and will only work with simple structured DXF files.

import ezdxf
from ezdxf import colors, bbox
from ezdxf.math import Matrix44
from ezdxf.addons import Importer

LAYER_RED = ("LAYER_RED", colors.RED)
LAYER_GREEN = ("LAYER_GREEN", colors.GREEN)
LAYER_BLUE = ("LAYER_BLUE", colors.BLUE)
GAP = 20


def merge(source, target):
    importer = Importer(source, target)
    # import all entities from source modelspace into target modelspace
    importer.import_modelspace()
    # import all required resources and dependencies
    importer.finalize()


def assign_layer(doc, layer_props):
    layer_name, layer_color = layer_props
    try:
        new_layer = doc.layers.new(layer_name)
    except ezdxf.DXFTableEntryError:
        print(f"layer '{layer_name}' already exist")
        return
    new_layer.dxf.color = layer_color
    for entity in doc.modelspace():
        entity.dxf.layer = layer_name


def shift_entities(msp, dx):
    m = Matrix44.translate(dx, 0, 0)
    for entity in msp:
        try:
            entity.transform(m)
        except NotImplementedError:
            entity.destroy()


target_dxf = ezdxf.readfile("base.dxf")
assign_layer(target_dxf, LAYER_RED)

cache = bbox.Cache()
for filename, layer_props in [
    # could be different DXF files of course
    ("base.dxf", LAYER_GREEN),
    ("base.dxf", LAYER_BLUE),
]:
    append_dxf = ezdxf.readfile(filename)
    # get extents of the merged modelspace of the target DXF,
    # here is a bounding box cache useful:
    extents = bbox.extents(target_dxf.modelspace(), cache=cache)
    # shift imported entities to the right:
    shift_entities(append_dxf.modelspace(), extents.size.x + GAP)
    # assign new layers to the imported entities
    assign_layer(append_dxf, layer_props)
    # import entities into the target DXF
    merge(append_dxf, target_dxf)


target_dxf.saveas("merged.dxf")

[easyw]

Hi @mozman
I'm trying this code but I get the following error:

LAYER_RED = ("LAYER_RED", colors.RED)
AttributeError: module 'ezdxf.colors' has no attribute 'RED'

I'm on:

ezdxf.version
(0, 17, 1, 'release')

I have 'solved' with this:

LAYER_RED =    ("LAYER_RED",    1)
LAYER_YELLOW = ("LAYER_YELLOW", 2)
LAYER_GREEN =  ("LAYER_GREEN",  3)
LAYER_CYAN =   ("LAYER_CYAN",   4)
LAYER_BLUE =   ("LAYER_BLUE",   5)
LAYER_MAGENTA =("LAYER_MAGENTA",6)

Thanks for your sample code and ezdxf tools