Here is my code:

import ezdxf
import numpy as np

x,y = np.meshgrid(range(-3,3),range(-3,3))
z = x**2 + y**2

doc = ezdxf.new('R2010', setup=True)

# Add a mesh entity
msp = doc.modelspace()

rows, cols = z.shape

# Add a MESH entity
mesh = msp.add_mesh()

msp.doc.layers.add("3d_surface")
mesh = msp.add_mesh(dxfattribs={"layer": "3d_surface"})

with mesh.edit_data() as mesh_data:
    # Create vertices from X, Y, and dem_data (Z)
    for i in range(rows):
        for j in range(cols):
            mesh_data.vertices.append((x[i, j], y[i, j], z[i, j]))

    # Create faces (each grid cell becomes a quadrilateral face)
    for i in range(rows - 1):
        for j in range(cols - 1):
            # Vertex indices for the four corners of the grid cell
            v0 = i * cols + j          # Top-left
            v1 = v0 + 1                # Top-right
            v2 = v0 + cols             # Bottom-left
            v3 = v2 + 1                # Bottom-right

            # Add a quadrilateral face
            mesh_data.faces.append((v0, v1, v3, v2))
    
dxf_file_path = 'example.dxf'
doc.saveas(dxf_file_path)

The created file can be read correctly by edrawings and on sharecad.org but not by freecad or autodesk.

Autodesk viewer gives the following:

AutoCAD-InvalidFile Sorry, the drawing file is invalid and cannot be viewed. – Please try to recover the file in AutoCAD, and upload it again to view.

TranslationWorker-InternalFailure Unrecoverable exit code from extractor: -1073741831

Am I doing something wrong?