ODF Export

MTEX support the following formats for storing and importing of ODFs:

Define an Model ODF

We will demonstrate the the import and export of ODFs at the following sample ODF which is defined as the superposition of several model ODFs.

cs = crystalSymmetry('cubic');
mod1 = orientation.byAxisAngle(xvector,45*degree,cs);
mod2 = orientation.byAxisAngle(yvector,65*degree,cs);
model_odf = 0.5*uniformODF(cs) + ...
  0.05*fibreODF(Miller(1,0,0,cs),xvector,'halfwidth',10*degree) + ...
  0.05*fibreODF(Miller(0,1,0,cs),yvector,'halfwidth',10*degree) + ...
  0.05*fibreODF(Miller(0,0,1,cs),zvector,'halfwidth',10*degree) + ...
  0.05*unimodalODF(mod1,'halfwidth',15*degree) + ...
  0.3*unimodalODF(mod2,'halfwidth',25*degree);
plot(model_odf,'sections',6,'silent')

Save as .mat file

The most simplest way to store an ODF is to store the corresponding variable model_odf as any other MATLAB variable using the command save. Note that you have to specify the variable name as a string.

% the filename - all files on this page are written into the temporary
% directory, so that running it does not overwrite the ODF files shipped
% with MTEX
fname = fullfile(tempdir, 'odf.mat');
save(fname,'model_odf')

Importing a .mat file is done simply by

load(fname)

Export as an generic ASCII file

By default and ODF is exported in an ASCII file which consists of a large table with four columns, where the first three column describe the Euler angles of a regular 5° grid in the orientation space and the fourth column contains the value of the ODF at this specific position.

% the filename
fname = fullfile(tempdir, 'odf.txt');

% export the ODF
export(model_odf,fname,'Bunge')

Other Euler angle conventions or other resolutions can by specified by options to export. Even more control you have, if you specify the grid in the orientation space directly.

% define a equispaced grid in orientation space with resolution of 5 degree
S3G = equispacedSO3Grid(cs,'resolution',5*degree);

% export the ODF by values at these locations
export(model_odf,fname,S3G,'Bunge','generic')

Export an ODF to an MTEX ASCII File

Using the options MTEX the ODF is exported to an ASCII file which contains descriptions of all components of the ODF in a human readable fashion. This format can be imported by MTEX without loss.

% the filename
fname = fullfile(tempdir, 'odf.mtex');

% export the ODF
export(model_odf,fname,'Bunge','interface','mtex')

Export to VPSC format

VPSC and other crystal plasticity codes do not read an ODF but a list of weighted orientations. The VPSC interface therefore draws a discrete sample from the ODF and writes it in the VPSC texture format - a three line header, the number of points, and then one row of Bunge Euler angles plus a weight per orientation.

Note that the interface has to be selected explicitly. Writing export(odf,fname,'VPSC') is not enough - 'VPSC' would be read as an unknown flag and the generic interface used instead.

fname = fullfile(tempdir, 'odfvpsc.txt');

export(model_odf,fname,'interface','VPSC','points',5000)

Let us look at the beginning of the resulting file

fid = fopen(fname);
for k = 1:6, disp(fgetl(fid)); end
fclose(fid);

texture exported by MTEX
B 5000
 107.10  150.76  172.21   0.0002000
 259.28   82.73   11.32   0.0002000

The number of orientations is controlled by the option 'points', which defaults to 10000. The counterpart, reading such a file back, is described in Import from VPSC.

delete(fname)