[acocic]

Hello to everybody,

I computed the flow in axial fan, in one blade passage and I want see the flow structure in meridian section - so I need to make a slice with cylindrical surface over the blades, and then to "flatten" that surface.

Is it possibly to do that in Paraview (paraFoam)? Any help would be more that welcome. Thanks in advance.

Alex.

[wyldckat]

Greetings Alex and welcome to the forum!

It's possible, but it requires two things:

1. That you are using ParaView 3.12 or 3.14, including the Python capabilities inside ParaView. The reason for this is that in ParaView 3.98, the necessary VTK filter is not present.
2. That you use the "Programmable Filter" instead of the normal "Slice" filter. The reason for this is because the "Cylinder" is an implicit function that for some reason they forgot to include in ParaView

Reference: http://www.paraview.org/pipermail/pa...ry/016019.html

Instructions:

1. Apply the "Programmable Filter" to the item you want to cut.
2. Use the following code in the first text edit box:
   

   input = self.GetInputDataObject(0, 0)
   inp_copy = input.NewInstance()
   inp_copy.ShallowCopy(input)
   inp_copy.UnRegister(None)
   cutter = vtk.vtkCutter()
   transf = vtk.vtkTransform()
   transf.RotateX(90)
   cyl = vtk.vtkCylinder()
   cyl.SetCenter(0,0,0)
   cyl.SetRadius(0.4)
   cyl.SetTransform(transf)
   cutter.SetCutFunction(cyl)
   cutter.SetInput(inp_copy)
   cutter.Update()
   self.GetOutputDataObject(0).ShallowCopy(cutter.GetOutputDataObject(0))

3. Notes on important details:
   • The cylinder is infinite, because it's an implicit function.
   • "cyl.SetRadius(0.4)" - defines the radius.
   • "cyl.SetCenter(0,0,0)" - defines the centre of the cylinder.
   • The transformation is done with these lines of code:

      transf = vtk.vtkTransform()
     transf.RotateX(90)

   • If more transformations are needed, see the list of methods here: http://www.vtk.org/doc/release/5.10/...Transform.html

Best regards,
Bruno

[acocic]

Hey Bruno,

It works just perfect!! Thank you very much! By default, I didn't have "Programmable filter" and Python support (I'm using OpenFOAM-1.6-ext and ParaView 3.12.0 which I compiled without Python support, I guess).

I downloaded then Paraview 3.12 again with

wget http://www.paraview.org/files/v3.12/...-x86_64.tar.gz

extract the files, and tried your code with "new" paraview on VTK data which I previously generated with foamToVTK. And then I got perfect cylindrical slice .

What is left for me is to connect this version of paraview with OpenFOAM, to be called with paraFoam.

Thanks to your other link

http://www.cfd-online.com/Forums/blo...-openfoam.html

it won't be a problem !

Best regards,
Alex.

[acocic]

Hello once again,

I just wanted to add some new insights on this topic. Actually, we don't have to modify paraFoam script, and OpenFOAM bashrc file. This paraView version I mentioned in previous thread supports OpenFOAM files, and you can open files with *.foam extension.

So I just created aliases, something like paraViewWithPython, which points to binary of new paraview. When you start this command in the root of the case, it won't automatically load the case data, but you can open *.foam file which is there, and then use Programmable filter.

Best regards,
Alex.

[wyldckat]

Hi Alex,

You use the following alias:

alias paraViewWP='touch case.foam && /long/path/to/ParaView-3.12.0/bin/paraview --data=case.foam'

It was based on the one shown here:http://openfoamwiki.net/index.php/Ho...using_ParaView

Best regards,
Bruno

[acocic]

Hi Bruno,

Once again, it works perfect! Now the data are automatically loaded, and Programmable filter & mighty Python support are there!

Thank you once again for all your support and answers!

Best regards,
Alex.

[mbgnfsr2]

hi Bruno
i have also try this scirpt, but in my case is not working. My output is in ensight format and i had to modify the script in order to deal with Multiblock Dataset. With the following script i don't get any error but the output is empty.

Here my code

def cut_cylinder(input_block, output_block):
    inp_copy = input_block.NewInstance()
    inp_copy.ShallowCopy(input_block.VTKObject)
    inp_copy.UnRegister(None)
    cutter = vtk.vtkCutter()
    transf = vtk.vtkTransform()
    transf.RotateX(90)
    cyl = vtk.vtkCylinder()
    cyl.SetCenter(0,0,0)
    cyl.SetRadius(0.04)
    cyl.SetTransform(transf)
    cutter.SetCutFunction(cyl)
    #cutter.SetInputConnection(inp_copy.GetOutputPort())
    cutter.SetInput(inp_copy)
    #cutter.SetInputData(inp_copy)
    #cutter.ShallowCopy(inp_copy) 
    cutter.Update()
    self.GetOutputDataObject(0).ShallowCopy(cutter.GetOutputDataObject(0))
    #output_block.ShallowCopy(cutter.GetOutputDataObject(0))


#============================================================================================
from paraview import vtk
from paraview.vtk.dataset_adapter import MultiCompositeDataIterator 
import math
from paraview.numpy_support import vtk_to_numpy
from paraview.vtk.dataset_adapter import numpyTovtkDataArray, vtkDataArrayToVTKArray
import numpy as np

iter = MultiCompositeDataIterator([inputs[0], output])

for input_block, output_block in iter: 
    cut_cylinder(input_block,output_block)

If i change from

cutter.SetInput(inp_copy)

to

cutter.SetInputData(inp_copy)

i simply get the parent geometry, but not the cut.
Does anyone know how i can make this script working.

Thanks very much

Stefano


I get

[wyldckat]

Greetings Stefano and welcome to the forum!

Can you provide a small example file with which I can reproduce this error?

In addition, I suggest that you use the "Merge Blocks" filter before applying this particular programmable filter, so that it makes it easier to at least test this programmable filter.

Beyond this, I suspect the problem is that you did not properly calibrate the settings for the position of the cylinder, namely these values were not changed:

transf.RotateX(90)
cyl.SetCenter(0,0,0)
cyl.SetRadius(0.04)

Best regards,
Bruno

[mbgnfsr2]

Dear Bruno
thanks very much for your replay. I check the centre, radius and axis and all are ok (The axis is z and the radius should be between 0.029 and 0.05).
I also try to use the filter merge block and after i applied your filter that posted at the top and still the result is the same of the input with no cut.
I manage to get something similar to what i was looking for using a coordinate transformation from Cartesian to cylindrical and after using the plane cut on the new geometry. but, in any case, would be nice to have also this filter working.
In attachment the small case as you have requested and if you manage to get something let me know. In the input there is only the mesh, but no variables.
Just to be clear at the moment i'm using Paraview 4.0 and i don’t know if the version is the source of the problem.
Thanks very much for your help

Best wishes

Stefano

[deandrade]

Hello everybody,

have you managed to find a solution for this problem in version 4.0?

I have the same problem as Stefano, changing that line makes the script work but it gives the parent geometry back.

Cheers!

[wyldckat]

Greetings to all!

I'll answer to all 3 posts here:

------------

@Stefano:

Originally Posted by mbgnfsr2

In attachment the small case as you have requested and if you manage to get something let me know. In the input there is only the mesh, but no variables.

My apologies for taking so very long to come back to your issue, but only today did I finally managed to take a look into this.

I tested with ParaView 4.1.0 with the following code and it worked just fine with the test case you provided:

input = self.GetInputDataObject(0, 0)
inp_copy = input.NewInstance()
inp_copy.ShallowCopy(input)
inp_copy.UnRegister(None)
cutter = vtk.vtkCutter()
transf = vtk.vtkTransform()
transf.RotateX(90)
cyl = vtk.vtkCylinder()
cyl.SetCenter(0,0,0)
cyl.SetRadius(0.04)
cyl.SetTransform(transf)
cutter.SetCutFunction(cyl)
cutter.SetInputData(inp_copy)
cutter.Update()
self.GetOutputDataObject(0).ShallowCopy(cutter.GetOutputDataObject(0))

Note: When I tried to use the "Merge Blocks" filter and then applied the programmable filter to it, then ParaView would crash

I've tested as well with ParaView 4.0.1 64-bit, which I downloaded as one of the pre-built packages from ParaView.org, and it worked as well.

Do notice that the critical detail here is that the radius needs to be changed from "0.4" to "0.04":

cyl.SetRadius(0.04)

I hope you managed to solve you problem a long time ago... it took me 8 months to get back to you

----------

@Jacopo:

Originally Posted by deandrade

have you managed to find a solution for this problem in version 4.0?

I have the same problem as Stefano, changing that line makes the script work but it gives the parent geometry back.

As shown in the code above, this code does work.
By the way, I hope you're using the "Programmable Filter", not the "Programmable Source".

----------

@Lourenço:

Originally Posted by lourencosm

Is there a way to auto-update the time step function,
So that the programmable filter finds the new values in paraview "play mode"??

Doesn't post #29 have the answer to your question?
If not, you'll have to provide more details, because I can't figure out what exactly you're looking for.

Best regards,
Bruno

[openfoammaofnepo]

Dear Bruno,

Which command here is for defining the axis direction of the cylindrical slice before is it flattened? Thanks.

Originally Posted by wyldckat

Greetings Alex and welcome to the forum!

It's possible, but it requires two things:

1. That you are using ParaView 3.12 or 3.14, including the Python capabilities inside ParaView. The reason for this is that in ParaView 3.98, the necessary VTK filter is not present.
2. That you use the "Programmable Filter" instead of the normal "Slice" filter. The reason for this is because the "Cylinder" is an implicit function that for some reason they forgot to include in ParaView

Reference: http://www.paraview.org/pipermail/pa...ry/016019.html

Instructions:

1. Apply the "Programmable Filter" to the item you want to cut.
2. Use the following code in the first text edit box:
   

   input = self.GetInputDataObject(0, 0)
   inp_copy = input.NewInstance()
   inp_copy.ShallowCopy(input)
   inp_copy.UnRegister(None)
   cutter = vtk.vtkCutter()
   transf = vtk.vtkTransform()
   transf.RotateX(90)
   cyl = vtk.vtkCylinder()
   cyl.SetCenter(0,0,0)
   cyl.SetRadius(0.4)
   cyl.SetTransform(transf)
   cutter.SetCutFunction(cyl)
   cutter.SetInput(inp_copy)
   cutter.Update()
   self.GetOutputDataObject(0).ShallowCopy(cutter.GetOutputDataObject(0))

3. Notes on important details:
   • The cylinder is infinite, because it's an implicit function.
   • "cyl.SetRadius(0.4)" - defines the radius.
   • "cyl.SetCenter(0,0,0)" - defines the centre of the cylinder.
   • The transformation is done with these lines of code:

      transf = vtk.vtkTransform()
     transf.RotateX(90)

   • If more transformations are needed, see the list of methods here: http://www.vtk.org/doc/release/5.10/...Transform.html

Best regards,
Bruno

[wyldckat]

Originally Posted by openfoammaofnepo

Which command here is for defining the axis direction of the cylindrical slice before is it flattened? Thanks.

Quick answer:

transf.RotateX(90)

Try without it and you will see the default orientation. You can also use the "Cylinder" source: menu -> Sources -> Cylinder - to test things with it.

[akashjangid]

Hello,

I computed the flow through a rotor(Diameter -1m) which is placed inside a wind tunnel.
Now i want to analyze flow at different span length of blades. So for that i need a cylindrical slice.
I am using 3.12.0 ParaVeiw version
I used this code but it does not show any output

input = self.GetInputDataObject(0, 0)
inp_copy = input.NewInstance() inp_copy.ShallowCopy(input)
inp_copy.UnRegister(None)
cutter = vtk.vtkCutter()
transf = vtk.vtkTransform()
transf.RotateX(90)
cyl = vtk.vtkCylinder()
cyl.SetCenter(0,0,0)
cyl.SetRadius(0.4)
cyl.SetTransform(transf)
cutter.SetCutFunction(cyl)
cutter.SetInput(inp_copy)
cutter.Update() self.GetOutputDataObject(0).ShallowCopy(cutter.Get OutputDataObject(0))

Can someone tell me why?
Thanks a lot!!

[wyldckat]

Hi Akash and welcome to the forum!

(I forgot to welcome you to the forum, when I replied to the message you had sent me!)

And thank you for posting your question here!
But there is one big question left unanswered: where exactly in space is your rotor?

Because this code assumes that the rotor is centred in "0,0,0" and its axis is aligned with Z.

If you don't know exactly where the rotor is in space, you can use the source "Cylinder" and move this cylinder to the location where your rotor is. This source is located in the menu "Sources -> Cylinder".

Then, knowing the position of this cylinder, it'll be easier to configure the script to do the section-cut in the right place!

Best regards,
Bruno

[akashjangid]

Hi wyldckat,

Yes my rotor is located at (0,0,0) and is rotating along z axis.

[acocic]

Hello Akash,

I think that you made some mistakes in the code, or it's just because of copying. For me Bruno's code works perfectly. So if you compare with it, there are slight differences. These are the paraview messages for your code, and possible solutions

Remark 1:
File "<string>", line 3
inp_copy = input.NewInstance() inp_copy.ShallowCopy(input)
^
SyntaxError: invalid syntax

This should be two lines,

inp_copy = input.NewInstance()
inp_copy.ShallowCopy(input)

Remark 2:
File "<string>", line 15
cutter.Update() self.GetOutputDataObject(0).ShallowCopy(cutter.Get OutputDataObject(0))
^
SyntaxError: invalid syntax

Also two lines:

cutter.Update()
self.GetOutputDataObject(0).ShallowCopy(cutter.Get OutputDataObject(0)

Remark 3: no space in last line
NOT

self.GetOutputDataObject(0).ShallowCopy(cutter.Get  OutputDataObject(0))

BUT

self.GetOutputDataObject(0).ShallowCopy(cutter.GetOutputDataObject(0))

If you used foamToVTK, and you analyze VTK data, you should choose vtkPolyData instead "Same as Input" in Output Data Set Type (just bellow Apply Reset Delete)

Best regards,
Alex.

[akashjangid]

Hello acocic,

I did the changes in the script as told by you.
But it is still showing some errors

Traceback (most recent call last):
File "<string>", line 21, in <module>
File "<string>", line 14, in RequestData
AttributeError: SetInput

Actually I'm a beginner in scripting python for ParaView.
Please help me with this ? Do i have to add any vtk modules for this ?

[akashjangid]

hey,

I installed paraveiw 3.14 and in that the script worked correctly
Thanks !!

[akashjangid]

Hello,

I got the cylindrical slice, now i want to flatten that surface
any idea how to do that ?
Thanks