# Paraview slice type - cylinder?

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 July 11, 2013, 07:18 #21 New Member   Christian Weiß Join Date: Jul 2013 Posts: 4 Rep Power: 5 hi thanks for your reply. I´m going to try this. meanwhile i got a hint to use the calculator filter to add an radius column to each point an then use the contour filter for only showing data at a certain radius. after i got that i flattened the "slice" with an caltulater doing something like this Code: `0*iHat+(asin(coordsY/(coordsX^2+coordsY^2)^(1/2))*(coordsX^2+coordsY^2)^(1/2))*jHat+coordsZ*kHat` this works verry well for me while i will never analyse more than a half cylinder because i just look at one blade. with best regards Christian wyldckat likes this.

July 22, 2013, 23:56
#22
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wayne.zhang
Join Date: Mar 2009
Location: Shanghai, Shanghai, P.R.China
Posts: 308
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p, li { white-space: pre-wrap; } Hi
it works for me here.
try this

Code:
```from paraview import vtk
import numpy as np

pdi = self.GetPolyDataInput()

c2p=vtkCellDataToPointData()
c2p.SetInputData(pdi)
c2p.Update()

pdo =  self.GetPolyDataOutput()
newPoints = vtk.vtkPoints()
numPoints = pdi.GetNumberOfPoints()

for i in range(0, numPoints):
coord = pdi.GetPoint(i)
x, y, z = coord[:3]
if x > 0:
r = np.sqrt(x*x+y*y)
t = np.arctan(x/y) + 0.5 * np.pi
if y < 0:
t = t + 1* np.pi
else :
r = np.sqrt(x*x+y*y)
t = np.arctan(x/y) +  1.5* np.pi
if y > 0:
t = t - 1* np.pi
newPoints.InsertPoint(i, r, t, 12*z)
pdo.SetPoints(newPoints)
here I export my result on a cyliner surface to a vtk file by "sample" utility. what I got is data in cell so I convert it to the point. so if you just load OF result directly, you just need to comment some of same
Attached Images
 CylindricalTransform.jpg (77.1 KB, 90 views)

Last edited by waynezw0618; July 23, 2013 at 04:56.

July 23, 2013, 04:57
this is the results
#23
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wayne.zhang
Join Date: Mar 2009
Location: Shanghai, Shanghai, P.R.China
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here is the results from the code
Quote:
 Originally Posted by waynezw0618 p, li { white-space: pre-wrap; } Hi it works for me here. try this Code: ```from paraview import vtk import numpy as np pdi = self.GetPolyDataInput() c2p=vtkCellDataToPointData() c2p.SetInputData(pdi) c2p.Update() pdi.GetPointData().AddArray(c2p.GetOutput().GetPointData().GetArray(0)) pdo = self.GetPolyDataOutput() newPoints = vtk.vtkPoints() numPoints = pdi.GetNumberOfPoints() for i in range(0, numPoints): coord = pdi.GetPoint(i) x, y, z = coord[:3] if x > 0: r = np.sqrt(x*x+y*y) t = np.arctan(x/y) + 0.5 * np.pi if y < 0: t = t + 1* np.pi else : r = np.sqrt(x*x+y*y) t = np.arctan(x/y) + 1.5* np.pi if y > 0: t = t - 1* np.pi newPoints.InsertPoint(i, r, t, 12*z) pdo.SetPoints(newPoints) #pdo.GetCellData().AddArray(pdi.GetCellData().GetArray(0)) pdo.GetPointData().AddArray(pdi.GetPointData().GetArray(0))``` here I export my result on a cyliner surface to a vtk file by "sample" utility. what I got is data in cell so I convert it to the point. so if you just load OF result directly, you just need to comment some of same
Attached Images
 a.jpg (36.4 KB, 77 views)

 October 23, 2013, 06:30 Slice with geometry #24 New Member   Abdalla Join Date: Oct 2013 Posts: 7 Rep Power: 5 Hi all, first of all, i am a beginner in using paraview. here at work i have to do some postprocessing for a motor flow simulation. Actually i have to test how to slice with a geometry. I have seen and also successfully tried to cylinder-slice the flow using the programmable filter as shown at the beginning of this thread. Since the programmable filter can not handle complex geometries i am wondering if i can use a CAD-Geometry (the bend cylinder is an .stl geometry file) to slice with. best regards, Abdalla

 October 26, 2013, 10:42 #25 Super Moderator   Bruno Santos Join Date: Mar 2009 Location: Lisbon, Portugal Posts: 9,931 Blog Entries: 39 Rep Power: 108 Greetings Abdalla and welcome to the forum! The programmable filter is only used because the cylinder shape is not present in the "Slice" filter. In your case, it's different and somewhat easier to do. Simply load up both data sets (the CFD results and the slice surface) and use the "Resample with DataSet" filter. I've finished just now writing the following post, which explains in more detail how to do this: http://www.cfd-online.com/Forums/par...tml#post459139 post #4 Best regards, Bruno __________________ OpenFOAM: FAQ | Getting started Forum: How to get help, to post code/output and forum guide What am I doing/planning: blog/wiki Read this before sending me PM

 February 11, 2014, 10:18 Get time in a Programmable Filter paraview 3.14 #26 New Member   German Blesio Join Date: Feb 2014 Posts: 2 Rep Power: 0 Hi to everyone. I'm new in Paraview (start learning this month for an intership) and I have some complications. I need to program a filter to change over time. I used Code: `t = inputs[0].GetInformation().Get(vtk.vtkDataObject.DATA_TIME_STEP()` in paraview 3.98. But in paraview 3.14 doesn't work and I couldn't found a way of fixing this "mistake". The reason for using paraview 3.14 is that I need to clip a cylinder. Thank you very much, and I'm sorry if I have any spelling/gramatical mistakes

 February 11, 2014, 15:43 #27 Super Moderator   Bruno Santos Join Date: Mar 2009 Location: Lisbon, Portugal Posts: 9,931 Blog Entries: 39 Rep Power: 108 Greetings gerble and welcome to the forum! I don't have time to test this right now, but some time ago I wrote/updated this post: http://www.cfd-online.com/Forums/ope...tml#post446333 post #6 After some further developments on the topic, the resulting conclusion was that the only guaranteed way to get the time in all ParaView versions was to use this: Code: `GetAnimationScene().TimeKeeper.Time` Problem is that this might depend on where it's being used. You might need to add this line to your code in the filter, before everything else: Code: `from paraview.simple import *` Please let us know if either one of these worked. Best regards, Bruno gerble likes this. __________________ OpenFOAM: FAQ | Getting started Forum: How to get help, to post code/output and forum guide What am I doing/planning: blog/wiki Read this before sending me PM

 February 11, 2014, 23:50 #28 New Member   German Blesio Join Date: Feb 2014 Posts: 2 Rep Power: 0 Unfortunatly it doesn't work out. I have tried in a Windows 7 system and in a Debian base computer. What happen is that when executing the paraview.simple import this messages appears: ":1: SyntaxWarning: import * only allowed at module level" and the result of GetAnimationScene().TimeKeeper.Time is 0.0 . Before writing in this forum I tried another sentences that requieres this definition and this error always appears. If I don't write that sentece, if I only try to get the time an error appears informing that 'GetAnimationScene' is not defined. On the other hand, I was thinking on define a variable in the python code so I can later modified through the "Animation View". It would consume more memory to make de animations (I think) but it will probably work equally to what I was trying. Is there a way of doing this? Sorry if I changed the issue of the Thread too much. Thank you very much for your answer! Last edited by gerble; February 12, 2014 at 12:47. Reason: spelling mistake

 February 16, 2014, 13:10 #29 Super Moderator   Bruno Santos Join Date: Mar 2009 Location: Lisbon, Portugal Posts: 9,931 Blog Entries: 39 Rep Power: 108 Hi German, After doing some trial-and-error-and-research, this programmable filter seems to work in ParaView 3.12.0: Code: ```def GetUpdateTimestep(algorithm): """Returns the requested time value, or None if not present""" executive = algorithm.GetExecutive() outInfo = executive.GetOutputInformation(0) if not outInfo.Has(executive.UPDATE_TIME_STEPS()): return None return outInfo.Get(executive.UPDATE_TIME_STEPS(),0) # This is the requested time-step. This may not be exactly equal to the # timesteps published in RequestInformation(). Your code must handle that # correctly req_time = GetUpdateTimestep(self) 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(0.1*(0.5+req_time)) cyl.SetTransform(transf) cutter.SetCutFunction(cyl) cutter.SetInput(inp_copy) cutter.Update() self.GetOutputDataObject(0).ShallowCopy(cutter.GetOutputDataObject(0))``` It's based on these sources of information: http://www.cfd-online.com/Forums/ope...tml#post428465 post #2 http://www.paraview.org/Wiki/ParaVie...s_.28Source.29This one is actually already coded for ParaView 3.98.x and 4.x. And some searching online. The "req_time" variable is the current time snapshot. As for global variables, they simply don't work, because the Python workspaces are completely independent, namely the ones on each filter and on the main Python shell. Best regards, Bruno __________________ OpenFOAM: FAQ | Getting started Forum: How to get help, to post code/output and forum guide What am I doing/planning: blog/wiki Read this before sending me PM

May 26, 2014, 08:07
#30
New Member

Christoph Rosebrock
Join Date: Jun 2010
Posts: 1
Rep Power: 0
Hello everyone,
I was looking for a possibility to create radial cuts and the solution presented by Bruno seemed to be a good solution. Using Paraview 4.1.0 I got the same error like akashjangid

Quote:
 Originally Posted by akashjangid Traceback (most recent call last): File "", line 21, in File "", line 14, in RequestData AttributeError: SetInput
Replacing
Code:
`cutter.SetInput(inp_copy)`
with

Code:
`cutter.SetInputData(inp_copy)`
keeps the code running in Paraview 4.1.0.

Thanks to all of you.

Christoph

 August 7, 2014, 07:59 #31 New Member   Stefano Rolfo Join Date: Aug 2014 Location: UK Posts: 3 Rep Power: 4 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 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 Code: `cutter.SetInput(inp_copy)` to Code: `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 Last edited by wyldckat; August 11, 2014 at 10:33. Reason: [QUOTE] -> [CODE]

 August 16, 2014, 13:01 #32 Super Moderator   Bruno Santos Join Date: Mar 2009 Location: Lisbon, Portugal Posts: 9,931 Blog Entries: 39 Rep Power: 108 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: Code: ```transf.RotateX(90) cyl.SetCenter(0,0,0) cyl.SetRadius(0.04)``` Best regards, Bruno __________________ OpenFOAM: FAQ | Getting started Forum: How to get help, to post code/output and forum guide What am I doing/planning: blog/wiki Read this before sending me PM

August 18, 2014, 13:30
#33
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Stefano Rolfo
Join Date: Aug 2014
Location: UK
Posts: 3
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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
Attached Files
 SmallInput.zip (8.7 KB, 4 views)

 November 13, 2014, 08:51 #34 New Member   Jacopo De Amicis Join Date: Mar 2012 Posts: 2 Rep Power: 0 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!

 December 2, 2014, 12:35 #35 New Member   Lourenço SM Join Date: Jul 2014 Location: Lisboa, Portugal Posts: 25 Rep Power: 4 Is there a way to auto-update the time step function, So that the programmable filter finds the new values in paraview "play mode"?? Thank you, Lourenço

April 5, 2015, 12:20
#36
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Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
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Greetings to all!

I'll answer to all 3 posts here:

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

@Stefano:
Quote:
 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:
Code:
```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.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":
Code:
`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:
Quote:
 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:
Quote:
 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"??
If not, you'll have to provide more details, because I can't figure out what exactly you're looking for.

Best regards,
Bruno
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April 25, 2016, 09:08
#37
Senior Member

Join Date: Jan 2013
Posts: 339
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Dear Bruno,

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

Quote:
 Originally Posted by wyldckat Greetings Alex and welcome to the forum! It's possible, but it requires two things: 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. 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: Apply the "Programmable Filter" to the item you want to cut. Use the following code in the first text edit box: Code: ```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))``` 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: 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

May 1, 2016, 19:14
#38
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Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
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Quote:
 Originally Posted by openfoammaofnepo Which command here is for defining the axis direction of the cylindrical slice before is it flattened? Thanks.
Code:
`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.
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