Display the vectors of 'fiber vector' plot at the center of each element rather than at each node
issueid=815 06-04-2019 02:31 AM
Junior Member
Display the vectors of 'fiber vector' plot at the center of each element rather than at each node

The current behaviour of the "fiber vector" plot option is to display an arrow/vector of the fiber direction at each node.
While this is entirely satisfactory in the bulk of a material, it causes problems when there is 1 'interface' node shared by elements of two different materials that have possibly different fiber directions.
The way this is currently handled seems to be: At that node, the 'fiber' vector indicates the sum (or average) of the fiber direction of each element that node is part of. This is visually confusing (the arrow is often pointing in a direction that is not actually aligned with any fiber) and it can be difficult to assess whether the fiber direction was defined correctly for these elements (or whether e.g. the element numbering scheme for those boundary elements unexpectedly follows a different pattern to the bulk of the material, which can sometimes happen depending on which meshing tools are used).

In some cases it's possible to work around this by using nearby elements to deduce the fiber direction of the element in question, but because the fiber direction is defined on an element-wise basis, it seems natural that it would also be displayed this way, and not for each node.

Is this a technical limitation or is there some other reason why the "fiber vector" plot option functions this way? I think it would be a useful fix if it is not difficult to implement.

regards,
Liam

PS: Meaningless "fiber vectors" are also displayed in an arbitrary default direction even for materials with no defined fibers. This is less of a functional complaint and a more trivial issue of visual clutter. It would be nice if this could be disabled but it is a less important issue than the above problem
Issue Details
Issue Number 815
Issue Type Feature
Project PostView
Category Unknown
Status Implemented
Priority Unknown
Suggested Version Unknown
Implemented Version (none)
Votes for this feature 0
Votes against this feature 0
Assigned Users (none)
Tags (none)




06-05-2019 07:05 AM
Lead Code Developer
Hi Liam,

I implemented your feature request regarding displaying vectors at the element centers. To be more precise, if the vector field is an element data field (like "fiber vector", which stores one vector per element), the vectors will be shown at the element's center. For nodal data fields (e.g. displacement), the vectors will still be rendered on the nodes.

The windows installer was updated on the web (mac and Linux will follow shortly) so please give this new version (PostView 2.4.4) a try and let us know what you find.

Cheers,

Steve

06-05-2019 07:32 AM
Lead Code Developer
Oh, I forgot to mention, the other issue you pointed out, I will probably have to address on the FEBio side, since PostView doesn't know whether a material is supposed to have fibers or not. I will look into that separately.

Cheers,

Steve

06-05-2019 09:39 PM
Junior Member
Thanks for the quick response.

The new feature (vector direction) seems to be working as intended but this version of postview is adding a new display bug.
In my previous version of postview (2.3.2) the vector arrows were "three dimensional" with appropriate shadows that interact with the lighting in the PostView graphics area.
In the new version I just downloaded (2.4.4) these arrows are just flat white when viewed from any angle which makes them difficult to see. I don't know if this problem was introduced by the change you just applied, or if there was some other graphics update in another intermediate postview version.

image for reference: https://imgur.com/bjqaJyj
[the one on the right is version 2.4.4, that's a typo]

regards,
Liam

06-06-2019 07:42 AM
Lead Code Developer
Hi Liam,

There was indeed an issue with the ambient lighting of the vector plots. I think I fixed it and uploaded a new installer. It's still version 2.4.4 so you first need to uninstall your latest install. Re-download version 2.4.4. from the website and then install that version. Let me know if you find any more issues.

Cheers,

Steve

06-07-2019 12:18 AM
Junior Member
Ok everything seems to be working correctly now.
Thanks for the help.
-Liam

06-10-2019 01:21 AM
Junior Member
I have just noticed that the ambient lighting vector problem seems to also be affecting the RGB axis indicator, which doesn't cause any difficulty at all but you might like to fix it in the next update

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