Segfault when exporting Abaqus Format

[conorbergin]

Always fails at the last *Element, I have tried this with several geometries, a simple example and its output below, some sort of out of bounds indexing error I would guess.

from netgen.occ import *

box = Box(Pnt(0,0,0),Pnt(10,10,10))

occmesh = OCCGeometry(box).GenerateMesh(maxh=5)

occmesh.Export("test.mesh","Abaqus Format")

*Heading
 "test.mesh"
*Node
1, 0, 0, 10
2, 0, 0, 0
3, 0, 10, 10
4, 0, 10, 0
5, 10, 0, 10
6, 10, 0, 0
7, 10, 10, 10
8, 10, 10, 0
9, 0, 0, 5
10, 0, 5, 10
11, 0, 10, 5
12, 0, 5, 0
13, 10, 0, 5
14, 10, 5, 10
15, 10, 10, 5
16, 10, 5, 0
17, 5, 0, 0
18, 5, 0, 10
19, 5, 10, 0
20, 5, 10, 10
21, 5, 5, 5
*Element, type=CPS3, ELSET=default
1, 2, 9, 12
2, 1, 10, 9
3, 3, 11, 10
4, 4, 12, 11
5, 9, 11, 12
6, 9, 10, 11
*Element, type=CPS3, ELSET=default
7, 6, 16, 13
8, 5, 13, 14
9, 7, 14, 15
10, 8, 15, 16
11, 14, 16, 15
12, 13, 16, 14
*Element, type=CPS3, ELSET=default
13, 2, 17, 9
14, 1, 9, 18
15, 6, 13, 17
16, 5, 18, 13
17, 9, 17, 18
18, 13, 18, 17
*Element, type=CPS3, ELSET=default
19, 4, 11, 19
20, 3, 20, 11
21, 8, 19, 15
22, 7, 15, 20
23, 11, 20, 15
24, 11, 15, 19
*Element, type=CPS3, ELSET=default
25, 2, 12, 17
26, 4, 19, 12
27, 6, 17, 16
28, 8, 16, 19
29, 12, 19, 16
30, 12, 16, 17
*Element, type=CPS3, ELSET=default