Problems with meshing non-convex domain

[elisk616]

Hi! I'm new to Neper and ran into a problem when I tried to run the code for the following shape (taken from the website)

neper -T -n 1000 -morpho gg -domain "cube(1.2,0.1,1.2)" -transform "cut(cylinder(0.3,0,0.3,0,1,0,0.15),cylinder(0.3,0,0.9,0,1,0,0.15),cylinder(0.9,0,0.3,0,1,0,0.15),cylinder(0.9,0,0.9,0,1,0,0.15))" -o 4_holes

It generated a .tess-file (although very slowly, it took 6929.048 secs, is that normal?) but I can't mesh it. It aborts during the 2D meshing, can anyone help me with this issue?

neper -M 4_holes.tess -faset none -format inp

======================== N e p e r =======================
Info : A software package for polycrystal generation and meshing.
Info : Version 4.8.1
Info : Built with: gsl|muparser|opengjk|openmp|nlopt|libscotch (full)
Info : Running on 48 threads.
Info : https://neper.info
Info : Copyright (C) 2003-2022, and GNU GPL'd, by Romain Quey.
Info : No initialization file found (`/home/z004wttr/.neperrc').

Info : ---------------------------------------------------------------
Info : MODULE -M loaded with arguments:
Info : [ini file] (none)
Info : [com line] 4_holes.tess -faset none -format inp
Info : ---------------------------------------------------------------
Info : Reading input data...
Info : - Reading arguments...
Info : Loading input data...
Info : - Loading tessellation...
Info : [i] Parsing file 4_holes.tess'... Info : [i] Parsed file 4_holes.tess'.
Info : Meshing...
Info : - Preparing... (cl = 0.02654) 100%
Info : - 0D meshing... 100%
Info : - 1D meshing... 100%
Info : - 2D meshing... 29% (0.25|0.83/95%| 4%| 1%)
*pbnodeqty = 11
nodeqty1d = 14
min_dist_max = 0.000000
Aborted (core dumped)

[rquey]

It takes 2500 secs on my laptop.

These tessellations do not necessarily mesh properly. You first need to apply regularization (-reg 1), but even so, there may be problems. If meshing fails, try to change the tessellation (different -id).