Fail to set the DIMENSION entities' layer

[SeanXunIC]

Thanks for your attention!
I tried to used the ezdxf entity.set_dxf_attrib function to change the layer of dimension from original_DIM_layer to new_DIM_layer (please kindly refer to the images and the attached dxf file). However, although I found the Layer of the dimensions are shown as the new_DIM_layer, when I turned off the new_DIM_layer, the dimensions are still shown. If I turn off the old one (original_DIM_layer), the dimensions are hidden. I'm wondering if there's something I'm doing wrong that's preventing me from successfully changing layers?

I've attached my code and the dxf file, thanks again!

import ezdxf

dxf_ori_path = ".\\dxf_original.dxf"
dxf_save_path = ".\\dxf_saved.dxf"

doc = ezdxf.readfile(dxf_ori_path)
msp = doc.modelspace()

# set the dim layer to copy
ori_dim_layer_name = 'original_DIM_layer'
new_dim_layer_name = 'new_DIM_layer'

# copy dimensions to new layer and remove the old ones
for entity in list(msp.query('*[layer=="{}"]'.format(ori_dim_layer_name))): 
    if entity.dxftype() != 'DIMENSION':
        continue

    new_entity = entity.copy()
    new_entity.set_dxf_attrib('layer', new_dim_layer_name)

    msp.unlink_entity(entity)
    msp.add_entity(new_entity)

doc.saveas(dxf_save_path)

# Then open the saved dxf file in AutoCAD

These are the dxf files on Google Drive
https://drive.google.com/drive/folders/1gRtUEGqntc-QcIA1e1f_SvfH-y8IrQ16?usp=drive_link

[mozman]

The DIMENSION entity stores the parameters for the dimension line. The visual representation is rendered into an anonymous geometry block "*Dnnnn" .

To change the layer of the visual representation you have to re-render the dimension line - the result will look different than the rendering from CAD applications, or you change the layer of all entities in the geometry block:

The copy/remove procedure of your code is not necessary, layers are not containers they are just attributes.

for dimension in msp.query(f'DIMENSION[layer=="{ori_dim_layer_name}"]'): 
    dimension.dxf.layer = new_dim_layer_name
    block = dimension.get_geometry_block()
    if block:
        for entity in block:
            entity.dxf.layer = new_dim_layer_name

[SeanXunIC]

Wow! Thank you so much, that's helpful!