[Paraview] [EXTERNAL] Coordinate system transformation

[Moreland, Kenneth]

Maybe somebody else understands better, but I am totally confused by what you are asking. It sounds like you have an original coordinate system x,y,z and a new coordinate system x1,y1,z1. Then you have a velocity vector u,v,w defined in the original coordinate system (x,y,z) that you want to transform to the new coordinate system (x1,y1,z1). This should be straightforward in either Calculator or Python Calculator or Programmable Filter. In fact, it sounds like you are already doing that. When you say, “however, those velocities correspond to (x1,y1,z1) coordinate system,” I assume that means that you have already done this transformation. What do you mean by “associate these… velocities to a new coordinate system”? You just have associated them with the new coordinate system.

-Ken


From: ParaView <paraview-bounces at paraview.org> on behalf of Manu V G <manu.gvm at gmail.com>
Date: Thursday, April 21, 2016 at 11:28 AM
To: "paraview at paraview.org" <paraview at paraview.org>
Subject: [EXTERNAL] [Paraview] Coordinate system transformation

Hello everyone!
Is it possible to create new local coordinate system (x1,y1,z1) and compute velocities in that (in short coordinate transformation) from the original system (x,y,z)? Google search did not help me much. And 'Transform' filter do not transform velocities to the new coordinate system (is a geometrical transformation).
Problem in detail :
I read a 3D velocity field in Paraview and compute orthogonal eigenvectors (x1,y1,z1) at a certain point 'O1' using 'Programmable Filter'. These eigenvectors (x1,y1,z1) act as basis for the new coordinate system with origin 'O1'. I am trying and just want to visualize velocity in plane z1=0. For this, I need to transform velocity field from original system to new coordinate system (x1,y1,z1). And I am trying solve it in the following way. Maybe there is simple way to do it Paraview.

From eigenvectors, I can specify the plane (z1=0) by using a 'Slice' filter. The velocities in that plane correspond to the global velocity (u,v,w) in (x,y,z) coordinate system. Then, I use transformation matrix to compute new velocity vector (u1,v1,w1) using 'Calculator' or 'Python Calculation'. However, those velocities correspond to (x1,y1,z1) coordinate system. So, is there a way to associate these newly computed velocities to a new coordinate system and plot them?
Or is there a different way to do it Paraview?

I would be very thankful for your suggestions and inputs.


Thanks in advance, yours
--
Manu V Goudar
Lab of Aero & Hydrodynamics,
Delft University of Technology
Delft, The Netherlands
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