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Question about "release from data file"

Posted Jun 16, 2015, 1:32 a.m. EDT Ray Optics, Results & Visualization Version 5.1, Version 5.2 5 Replies

Xinlin Feng
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I'm trying to introducing some data to COMSOL in ray tracing module, and when I introduce my txt file into it and compute, I can see no light trace like before. I set the Index of first column containing position data as 0 and the Index of first column containing direction data as 3 and my input form is like:
Px Py Pz Kx Ky Kz
I cant figure out where I have made a mistake, because there is no alert or error report.
anyone know the right form of inputting data? Thanks
5 Replies Last Post Feb 12, 2016, 5:41 p.m. EST
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Hello Xinlin Feng

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Sepideh Ramezani
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Posted: 9 years ago Jul 29, 2015, 11:44 a.m. EDT
I have the same question.

Is there any tutorial or example of this section for the particle tracing?

I have the same question. Is there any tutorial or example of this section for the particle tracing?
David Reens
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Posted: 9 years ago Aug 26, 2015, 5:49 p.m. EDT
I also have this problem.

How can COMSOL offer a "release from file" option without telling us how this file should be formatted? The manual only instructs us to specify which column contains the first position coordinate. How about the first direction coordinate? How about delimiters- tab or space or comma? Is this a text file or spreadsheet?

The manual also says that values of auxiliary variables can also be specified. How?
I also have this problem. How can COMSOL offer a "release from file" option without telling us how this file should be formatted? The manual only instructs us to specify which column contains the first position coordinate. How about the first direction coordinate? How about delimiters- tab or space or comma? Is this a text file or spreadsheet? The manual also says that values of auxiliary variables can also be specified. How?
David Reens
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Posted: 9 years ago Aug 26, 2015, 7:33 p.m. EDT
Well I've answered some of my question myself. I still don't know about auxiliary definitions, but this has worked:

% Comments can go after "%" symbols
% Data follows with qx,qy,qz each row. Tab works, as well as spaces or commas.
0 0 0
0 0 1
0 0 2
0 0 3
0 1 0

Beware- at least in my model the units in the file are assumed to be meters even though my geometry unit is millimeters. If you aren't seeing any rays maybe its because they're outside the physical domain on which you've defined your geometric ray optics physics.
Well I've answered some of my question myself. I still don't know about auxiliary definitions, but this has worked: % Comments can go after "%" symbols % Data follows with qx,qy,qz each row. Tab works, as well as spaces or commas. 0 0 0 0 0 1 0 0 2 0 0 3 0 1 0 Beware- at least in my model the units in the file are assumed to be meters even though my geometry unit is millimeters. If you aren't seeing any rays maybe its because they're outside the physical domain on which you've defined your geometric ray optics physics.
Alexey Trukhin
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Posted: 9 years ago Feb 7, 2016, 7:23 a.m. EST

Well I've answered some of my question myself. I still don't know about auxiliary definitions, but this has worked:

% Comments can go after "%" symbols
% Data follows with qx,qy,qz each row. Tab works, as well as spaces or commas.
0 0 0
0 0 1
0 0 2
0 0 3
0 1 0

Beware- at least in my model the units in the file are assumed to be meters even though my geometry unit is millimeters. If you aren't seeing any rays maybe its because they're outside the physical domain on which you've defined your geometric ray optics physics.

I confirm that even if your model set in millimeters, when reading from the file your coordinates, COMSOL assumes them as set in meters. Pay attention to the unit system chosen in COMSOL!
[QUOTE] Well I've answered some of my question myself. I still don't know about auxiliary definitions, but this has worked: % Comments can go after "%" symbols % Data follows with qx,qy,qz each row. Tab works, as well as spaces or commas. 0 0 0 0 0 1 0 0 2 0 0 3 0 1 0 Beware- at least in my model the units in the file are assumed to be meters even though my geometry unit is millimeters. If you aren't seeing any rays maybe its because they're outside the physical domain on which you've defined your geometric ray optics physics. [/QUOTE] I confirm that even if your model set in millimeters, when reading from the file your coordinates, COMSOL assumes them as set in meters. Pay attention to the unit system chosen in COMSOL!
Christopher Boucher COMSOL Employee

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Posted: 9 years ago Feb 12, 2016, 5:41 p.m. EST
Hi David, Alexey:

Currently the Release from Data File feature interprets the particle positions using the model base unit, which is defined by selecting an option from the "Unit System" list in the settings window for the root node.

I agree that this behavior is very confusing, especially considering that the Release from Grid node does use the Geometry unit instead of the model base unit -- the exact opposite behavior as the Release from Data File. We hope to make the treatment of length units more consistent among all particle release features in the next version. We will also take steps to make the documentation of the Release from Data File feature more comprehensive.

Best Regards,
Christopher Boucher
Hi David, Alexey: Currently the Release from Data File feature interprets the particle positions using the model base unit, which is defined by selecting an option from the "Unit System" list in the settings window for the root node. I agree that this behavior is very confusing, especially considering that the Release from Grid node does use the Geometry unit instead of the model base unit -- the exact opposite behavior as the Release from Data File. We hope to make the treatment of length units more consistent among all particle release features in the next version. We will also take steps to make the documentation of the Release from Data File feature more comprehensive. Best Regards, Christopher Boucher

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