Extra SPLINE Display Issue in ezdxf DXF Viewer

[Alewep]

Hello,
I'm trying to display this DXF file using dxf view, but it shows an extra SPLINE:

I don't see this SPLINE in AutoCAD:

How can I prevent it from being displayed with ezdxf?

the dxf file :
00690026_374910a12d8b4a4c1fc5f706_step_000.zip

[mozman]

This is an floating point imprecision issue (again). I have no real solution for that now.

• The SPLINES in your files have a degree of 2.
• A clamped B-spline requires degree+1 equal knots at the beginning and the end to be clamped, which means the curve starts at the first control point and ends at the last control point.

Some knot-vectors of your SPLINES look like this:

#276: [0.5, 0.5, 0.5000000000000006, 0.541666666666667, 0.541666666666667, ...]

As you see the first 3 knot values are not exactly equal and this causes the problem.
A simple fix for your files to round the knot values:

import ezdxf

doc = ezdxf.readfile("1284_v1.dxf")

for spline in doc.entitydb.query("SPLINE"):
    spline.knots = [round(k, 7) for k in spline.knots]
doc.saveas("1284_v1_fixed.dxf")

The point calculation and rendering is fixed:

This is of course not a general solution for this issue!