[Paraview] [EXTERNAL] Coordinate system transformation

[Manu V G]

> I’m still not sure what you mean by “create the new coordinate system.” Do you perhaps mean that you want ParaView to render the data using positions in x1,y1,z1 instead of x,y,z?

Yes. Thanks a lot. Now I understand why I was not so clear.


>A straightforward way to do this is to use the calculator filter to perform your matrix transformation from x,y,z to x1,y1,z1 on the point coordinates array (names “coords” in the ParaView GUI) and then click the checkbox labeled “Coordinate Results”. That will write the results of the transformation into the point coordinates array and will have the effect of moving the data.

Thank you. I didn't know it was so simple to do this.


Warm Regards
Manu






>
> From: Manu V G <manu.gvm at gmail.com>
> Date: Thursday, April 21, 2016 at 4:28 PM
> To: Kenneth Moreland <kmorel at sandia.gov>
> Cc: "paraview at paraview.org" <paraview at paraview.org>
> Subject: Re: [EXTERNAL] [Paraview] Coordinate system transformation
>
>
>
> Thanks for your quick reply.
> Sorry, I was not very clear. I will try to explain clearly here.
>
> > 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.
>
> I don't have the new coordinate system (x1,y1,z1) loaded in paraview. I compute the origin and unit vectors of new coordinate system that I need to create  in paraview using the programmable filter.
>
> > 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.
>
> Yes. I multiple the velocity vector in (x,y,z) system at all points by transformation matrix. Hence, a new vector is created in (x,y,z) coordinate system.
>
> > 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.
>
> I meant the new vector created is associated with (x1,y1,z1) coordinate system. Now, I want to create the new coordinate system (x1,y1,z1) and associate the new vector to it. If I create a slice normal to 'y' direction in paraview, I want it to create a slice normal to 'y1' in new coordinate system.
>
> I hope I am clear?..
>
> Thanks and regards
> Manu
>
>
>
> >
> > 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




-- 
Manu