# 3.2. linearODF file

## Purpose

The

*.linearODF files are used to provide ODF intensity data from macro texture measurements. The files are read in by DAMASK as defined in the texture section of the

material.config file. The data is then used to sample single orientations using the hybridIA scheme [1] where the number of orientations needed is automatically determined by DAMASK. Finally the orientations are randomly assigned to the integration (FEM) or Fourier (spectral solver) points.

## Syntax

The file starts with a three line header followed by an empty line before the list of intensities.
The first header line contains three numbers specifying the maximum Euler angles of the ODF $max\ \varphi_1$, $max\ \Phi$, and $max\ \varphi_2$.
The second line is used to specify the step (bin) size for the three Euler angles $\Delta \varphi_1$, $\Delta \Phi$, and $\Delta \varphi_2$.
The third line determines the voxel (bin) placement. It can either read "voxel boundary at origin" or "voxel center at origin".
After one empty line the list of ODF intensities follows. This list is sorted by Euler angles with $\varphi_2$ running first, then $\Phi$ and finally $\varphi_1$.
I.e. the first intensity value is for the Euler angles (0, 0, 0), the second for (0, 0, $\Delta \varphi_2$), the third for (0, 0, $2\Delta \varphi_2$) and so on until (0, 0, $max\ \varphi_2$), then follow (0, $\Delta \Phi$, 0), (0, $\Delta \Phi$, $\Delta \varphi_2$) and so on all the way to ($max\ \varphi_1$, $max\ \Phi$, and $max\ \varphi_2$).
In total $max\ \varphi_1 / \Delta \varphi_1 * max\ \Phi / \Delta \Phi * max\ \varphi_2 / \Delta \varphi_2$ intensiteis must be specified. The intensities do not need to be normalized, this is automatically handled by DAMASK.

## Example

The sample files provided with DAMASK is given here in short form

1 header
phi1 PHI phi2 intensity
2.5 2.5 2.5 0.560461
2.5 2.5 7.5 0.603906
2.5 2.5 12.5 0.756228
2.5 2.5 17.5 0.979027
2.5 2.5 22.5 1.15566
...
...
...
357.5 177.5 332.5 1.1835
357.5 177.5 337.5 0.922203
357.5 177.5 342.5 0.711097
357.5 177.5 347.5 0.601503
357.5 177.5 352.5 0.58171
357.5 177.5 357.5 0.620167

## References

[1] |
P. Eisenlohr, F. Roters: Selecting sets of discrete orientations for accurate texture reconstruction, Computational Materials Science **42** (2008) 670 - 678 |