Identifying connected clusters

[vishankkumar]

Is it possible to create a flag that identify the connected spheres, where connection is defined if the distance between two particles of radius r1 and r2 is less than r1 + r2? I wanted to generate a 2 phase microstructure along with additional phases for connected clusters of phase 1 and phase 2.

[kip-hart]

Hi Vishan,

It's possible to do this, although it may take the code a long time to run if it has to check if sphere "i" and sphere "j" are close enough to add a phase between them. Another approach would be to create a PolyMesh from the spheres of phase 1 and 2, then add spheres of phase 3+ to the facets between phases 1 and 2. Here's the steps:

1. Create a SeedList of phases 1 and 2 (seeds_12)
2. Position those seeds in the domain
3. Create a PolyMesh (pmesh_12) from seeds_12
4. For each facet neighbor pair (pmesh_12.facet_neighbors) in the PolyMesh:
   a. Check if phase numbers (pmesh_12.phase_numbers) are unique
   b. Check if the distance between the seeds is close enough, etc
   c. Create a seed (or multiple seeds) of phase 3+ if (a) and (b) checks pass
   d. Position the seed(s) on that facet
   e. Append seed to a new SeedList (seeds_3)
5. Define new SeedList seeds_all = seeds_12 + seeds_3
6. Create a PolyMesh (pmesh_all) from seeds_all
7. Create a TriMesh from pmesh_all

I wrote something similar to this in the foam.py example. First a PolyMesh is created from the voids, then circles of the foam phase are added to the facets between the voids.

Let me know how it goes and feel free to follow up. I'm happy to help.

Best,
Kip