[visit-developers] 2d meshes and 3d vectors

Miller, Mark C. miller86 at llnl.gov
Wed Jul 22 16:30:46 EDT 2015


Hi Sveta,

Hmm. I see the picture and think I understand the meaning of 3D vectors on a 2D mesh.

I am just trying to understand what the source of that data is? Where's it comming from? Whats driving the condition of having 2D mesh data with vectors defined on the mesh that have a 3rd component? Ordinarily, for purely 2D problems, only 2D entities make mathematical sense. If you are taking curls of vectors in 2D, then the magnitude of the result can be thought of as a component of a vector out of the 2D plane but that is really just a conceptual convenience (hxxps://www.physicsforums.com/threads/curl-in-2d-is-a-vector-or-a-scalar.745388/). Its really a scalar value that you wind up with. You don't all of the sudden wind up adding a 3rd dimension to a setting which was originally purely 2D. This is the reason for my question…why do you have 3D vectors on a 2D mesh to begin with?

From: sveta <sveta at txcorp.com<mailto:sveta at txcorp.com>>
Reply-To: "visit-developers at elist.ornl.gov<mailto:visit-developers at elist.ornl.gov>" <visit-developers at elist.ornl.gov<mailto:visit-developers at elist.ornl.gov>>
Date: Wednesday, July 22, 2015 1:16 PM
To: "visit-developers at elist.ornl.gov<mailto:visit-developers at elist.ornl.gov>" <visit-developers at elist.ornl.gov<mailto:visit-developers at elist.ornl.gov>>
Subject: Re: [visit-developers] 2d meshes and 3d vectors

Hi Mark,
These are vectors sticking into the 3d dimension sitting on a 2d thing
(see attached).  Yes, the mesh is 2d meaning that there are only x and y
values.
Thanks,
S

On 7/22/15 2:10 PM, Miller, Mark C. wrote:
First, wanna make sure what you mean by 2d mesh. You have a mesh in
which z coord is always zero? If so, yeah, VisIt won't let you have
vectors on that mesh with more than two components. If you don't have
option of applying an operator of some kind (like transform with
x-rotate by a tiny fraction of a degree), then probably best thing is to
accomodate this in the plugin.

Out of curiosity thoug, can you describe the use case for 3D vectors on
a 2D mesh? It might be best if we ultimately get rid of the constraints
prohibiting this in VisIt.

Mark


From: Sveta <sveta at txcorp.com<mailto:sveta at txcorp.com> <mailto:sveta at txcorp.com>>
Reply-To: "visit-developers at elist.ornl.gov<mailto:visit-developers at elist.ornl.gov>
<mailto:visit-developers at elist.ornl.gov>"
<visit-developers at elist.ornl.gov<mailto:visit-developers at elist.ornl.gov> <mailto:visit-developers at elist.ornl.gov>>
Date: Wednesday, July 22, 2015 12:49 PM
To: "visit-developers at elist.ornl.gov<mailto:visit-developers at elist.ornl.gov>
<mailto:visit-developers at elist.ornl.gov>"
<visit-developers at elist.ornl.gov<mailto:visit-developers at elist.ornl.gov> <mailto:visit-developers at elist.ornl.gov>>
Subject: [visit-developers] 2d meshes and 3d vectors

     Hi everybody,

     What is the best way to be able to deal with 3d vectors and their
     magnitudes, when the mesh is 2d?

     I could check in Vs plugin for this and create a 3d mesh if the the
     vector has 3 components.  But is there a better way?  Can I set a mesh
     dimensionality through some function call of VisIt?  I cannot not go
     interactively through elevate operator as we have embeddded VisIt in
     our
     application.

     Thank you,
     SVeta



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://elist.ornl.gov/pipermail/visit-developers/attachments/20150722/5de4d883/attachment.html>


More information about the visit-developers mailing list