Tutorial for Simple DXF Entities

These are basic graphical entities located in an entity space like the modelspace or a block definition and only support the common graphical attributes.

The entities in the following examples are always placed in the xy-plane of the WCS aka the 2D drawing space. Some of these entities can only be placed outside the xy-plane in 3D space by utilizing the OCS, but this feature is beyond the scope of this tutorial, for more information about that go to: Tutorial for OCS/UCS Usage.

Prelude to all following examples:

import ezdxf
from ezdxf.gfxattribs import GfxAttribs

doc = ezdxf.new()
doc.layers.new("ENTITY", color=1)
msp = doc.modelspace()
attribs = GfxAttribs(layer="ENTITY")

See also

Point

The Point entity marks a 3D point in the WCS:

point = msp.add_point((10, 10), dxfattribs=attribs)

All Point entities have the same styling stored in the header variable $PDMODE, for more information read the reference of class Point.

See also

Line

The Line entity is a 3D line with a start- and an end point in the WCS:

line = msp.add_line((0, 0), (10, 10), dxfattribs=attribs)

See also

Circle

The Circle entity is an OCS entity defined by a center point and a radius:

circle = msp.add_circle((10, 10), radius=3, dxfattribs=attribs)

See also

Arc

The Arc entity is an OCS entity defined by a center point, a radius a start- and an end angle in degrees:

arc = msp.add_arc((10, 10), radius=3, start_angle=30, end_angle=120, dxfattribs=attribs)

The arc goes always in counter-clockwise orientation around the z-axis more precisely the extrusion vector of OCS, but this is beyond the scope of this tutorial.

The helper class ezdxf.math.ConstructionArc provides constructors to create arcs from different scenarios:

This example creates an arc from point (10, 0) to point (0, 0) passing the point (5, 3):

from ezdxf.math import ConstructionArc

# -x-x-x- snip -x-x-x-

arc = ConstructionArc.from_3p(
    start_point=(10, 0), end_point=(0, 0), def_point=(5, 3)
)
arc.add_to_layout(msp, dxfattribs=attribs)

See also

Ellipse

The Ellipse entity requires DXF R2000 or newer and is a true WCS entity. The ellipse is defined by a center point, a vector for the major axis, the ratio between major- and minor axis and the start- and end parameter in radians:

ellipse = msp.add_ellipse(
    (10, 10), major_axis=(5, 0), ratio=0.5, start_param=0, end_param=math.pi, dxfattribs=attribs
)

When placed in 3D space the extrusion vector defines the normal vector of the ellipse plane and the minor axis is the extrusion vector cross the major axis.

See also

Further Tutorials