The support for transparency was added to the DXF file format in revision R2004.
The raw transparency value stored as 32 bit value in the DXF namespace as
transparency attribute, has a range from 0 to 255 where 0 is fully
transparent and 255 if opaque and has the top byte set to
For a more easy usage all graphical entities support the
transparency property to get and set the
transparency as float value in the range frem 0.0 to 1.0 where 0.0 is opaque and
1.0 is fully transparent. The transparency value can be set explicit in the
entity, by layer or by block.
import ezdxf doc = ezdxf.new() msp = doc.modelspace() line = msp.add_line((0, 0), (10, 0)) line.transparency = 0.5
Autodesk Knowledge Network: About Making Objects Transparent
BricsCAD Help Center: Entity Transparency