Unable to index twin boundaries.

[Carlos Ávila]

Any thoughts of why this (below) isn't working? The twinning law is 85º<02-21>.

Apparently the error is in the "isTwinning" line, but the code is almost the exact copy of the example in the documentation page.

Sdir = symmetrise(Miller(0,2,-2,1,ebsd('Hematite').CS,'UVTW'));

R_twin = rotation('axis',Sdir,'angle',85*degree);

isTwinning = angle(grains.boundary('He','He').misorientation,R_twin) < 5*degree;

R_twin_bounds = grains.boundary(isTwinning);

Cheers.

[Ralf Hielscher]

Could you please try

R_twin = orientation('axis',Sdir,'angle',85*degree,ebsd('Hematite').CS,ebsd('Hematite').CS);

Thank you very much,

Ralf.

[Carlos Ávila]

Hello Ralf,
sorry, but it didn't work.

Error message is in the image. Can't figure it out.

I was wondering about the arguments of the "angle" command. We are comparing two misorientation relations, but shouldn't we be comparing the products of such misorientations.
Not sure if I was clear enough. Anyway, can you help?

Thank you.
Carlos Ávila.

[Ralf Hielscher]

Hi Carlos,

I think the mistake is that you symmetrise the rotational axis which gives you Sdir. As an result R_twin is a list of rotations and  angle( ... ) does not know what to do. 

When working with misorientations MTEX automatically knows that he has to consider symmetric equivalent orientations.

Please try the following

%// define the misorientation axis
Sdir = Miller(0,2,-2,1,ebsd('Hematite').CS,'UVTW');

%// define the twinning misorientation

R_twin = orientation('axis',Sdir,'angle',85*degree,ebsd('Hematite').CS,ebsd('Hematite').CS);

%// check the angle between boundary misorientations and twinning misorientation is small
gB_He = grains.boundary('He','He');
isTwinning = angle(gB_He.misorientation,R_twin) < 5*degree;

R_twin_bounds = gB_He(isTwinning);

Ralf.

On Wednesday, September 2, 2015 at 3:11:03 PM UTC+2, Carlos Ávila wrote:

[Carlos Ávila]

Well the error message did change. Still didn't work though.
I'm sure this is the correct twinning law and that the error is not in the R_twin line.
Thanks Ralf.

On Thursday, 3 September 2015 14:22:12 UTC-3, Ralf Hielscher wrote:

Hi Carlos,

I think the mistake is that you symmetrise the rotational axis which gives you Sdir. As an result R_twin is a list of rotations and  angle( ... ) does not know what to do. 

When working with misorientations MTEX automatically knows that he has to consider symmetric equivalent orientations.

Please try the following

%// define the misorientation axis
Sdir = Miller(0,2,-2,1,ebsd('Hematite').CS,'UVTW');

%// define the twinning misorientation
R_twin = orientation('axis',Sdir,'angle',85*degree,ebsd('Hematite').CS,ebsd('Hematite').CS);

%// check the angle between boundary misorientations and twinning misorientation is small

isTwinning = angle(grains.boundary('He','He').misorientation,R_twin) < 5*degree;

R_twin_bounds = grains.boundary(isTwinning);

[Ralf Hielscher]

Sorry, I made an mistake in my previous reply. I edited it. Look at it back please.

Thx.

[Carlos Ávila]

Huh, how about that. It worked.
I guess it's because the size of the "isTwinning" didn't match the grain.boundaries right?
Anyway thank you very much Ralf, won't make mistakes like that again.

Carlos.

[Ralf Hielscher]

right :)

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Ralf Hielscher                   Tel: +371-531-38556
Fakultät für Mathematik               +371-531-22200 (Sekr.)
Technische Universität Chemnitz  Fax: +371-531-22109
Reichenhainer Str. 39            E-mail: ralf.hi...@mathematik.tu-chemnitz.de
D-09126 Chemnitz                 http://www.tu-chemnitz.de/~rahi
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