Need help on generating large number of grains with mesh

[ashokambig]

Dear Neper members,
I need a help on creating a domain with at least 25000 grains in a 3D domain.
This is for a micro structure simulation at nanometer level using abaqus.
Size of the domain can be anything. With such large grains number we can expect large number of elements.
Therefore I would like to restrict number of elements to 20 millions.
Shape of the grains can be of standard voronoi type, but I would like to have almost same shape and sphericity of grains.

Summary of my problem:
Domain : can be anything (e.g cube with sides (1000,1000,1000))
Tesselation type : Standard Voronoi, almost equal sized grain (shape and sphericity almost same)
Number of grains : ~ 25000
Maximum number of finite elements ~ 20 millions (can be a bit higher too)

I have tried below option. This works for 6000 grains. But I dont know how I can improve it to generate higher number of grains.
Can anyone help me?

---

export OMP_NUM_THREADS=1
neper --rcfile none -T -n 6000 -domain "cube(0.02,0.015,0.015)" -morpho gg -o abq_input
neper --rcfile none -M abq_input.tess -elttype tet -order 2 -rcl 0.5 -faset none -format inp

Regards
Ashok

[rquey]

I may be missing something, but you are getting 6000 cells simply because you are using -n 6000. If you want more cells, use a larger value.