3.4. Seeds file format

---

Content

A valid seeds file contains the following [optional] information

• a list of positions and
  • crystal orientations and/or
  • microstructure indices
• [number of seed points]
• [size of periodic box]
• [origin of periodic box]
• [minimum grid resolution to guarantee realization of all seed points upon Voronoi tessellation]
• [seed value of random number generator]

---

Coordinates

The seed coordinates correspond to fractional positions within the dimensions of the periodic box. Therefore, it is sensible to restrict the coordinates to the range between 0 and 1.

---

Seed property

Each seed point can specify the following two information.

Bunge (z-x-z) Euler angles

By using the column headings 1_Euler, 2_Euler, and 3_Euler the Euler angles (in degrees) characterizing the crystal orientation of the corresponding seed point are determined.

Microstructure index

Data given under the column heading microstructure is used to override the consecutive assignment of numerical IDs for the seed points. Overriding the standard behavior might be useful if a material.config file corresponding to a certain order of seed points is already existing.

---

Examples

Crystal orientations

An exemplary seeds file containing

• 20 points
• minimum grid resolution of 16 x 16 x 16

and specifying the crystal orientation for each seed point would read:

4   header
grid   a 16   b 16   c 16
microstructures   20
randomSeed   0
1_pos   2_pos   3_pos   1_Euler   2_Euler   3_Euler
  0.375488     0.161813     0.891040   197.572861    16.816409   129.422844
  0.187988     0.849313     0.953540   257.468172    53.250534   157.331503
  0.750488     0.349313     0.953540   216.994815    94.418518   251.147231
  0.312988     0.099313     0.891040   196.157946    55.870978    21.681170
  0.562988     0.536813     0.703540   152.515728   139.769395   240.036018
  0.750488     0.036813     0.641040   232.521881    73.749222   241.429633
  0.812988     0.724313     0.016040   157.531396   135.503513    75.737722
  0.187988     0.161813     0.266040   321.038280    27.209843    46.413467
  0.562988     0.286813     0.203540   346.918594    87.495569   113.554206
  0.937988     0.599313     0.953540   138.038947    99.827132   130.935878
  0.937988     0.349313     0.578540   285.021014   118.092004   205.270837
  0.812988     0.661813     0.453540   190.402171    56.738068   157.896545
  0.125488     0.411813     0.203540   204.496042    95.031265   355.814582
  0.625488     0.224313     0.578540   333.214790    82.133355    36.736132
  0.687988     0.161813     0.891040    25.572981   164.242648    75.195632
  0.625488     0.161813     0.766040    31.366548    76.392403    58.071426
  0.437988     0.724313     0.266040     7.278623    77.044663   235.118997
  0.437988     0.099313     0.641040   299.743144    76.475096    91.184977
  0.937988     0.911813     0.828540   280.136430    27.439718   167.871878
  0.437988     0.411813     0.516040   313.204373    68.676053    87.993213

Microstructure indices

An exemplary seeds file containing

• 4 points
• suggested domain size of 2 x 1 x 0.5
• suggested origin of domain at 1 : 1 : 0.5

with deliberately assigned microstructure indices would read:

3   header
size   x 2.0   y 1.0   z 0.5
origin   x 1.0   y 1.0   z 0.5
1_pos   2_pos   3_pos   microstructure
  0.375488     0.161813     0.891040   3
  0.187988     0.849313     0.953540   1
  0.750488     0.349313     0.953540   2
  0.312988     0.099313     0.891040   4