# Latest

**URL:** https://discourse.vtk.org/latest.md?page=201

[Latest](https://discourse.vtk.org/latest.md) · [Categories](https://discourse.vtk.org/categories.md) · [Tags](https://discourse.vtk.org/tags.md)

**Page:** 202

---

## [Undo redo of the widgets](https://discourse.vtk.org/t/undo-redo-of-the-widgets/4105)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 2\
**Last updated:** [September 3, 2020, 11:03am UTC](https://discourse.vtk.org/t/undo-redo-of-the-widgets/4105 "2020-09-03T11:03:14Z")

</div>

Hi, I have a general question. I wonder if there is any class in vtk to track the status of the widgets to undo redo changes of the widgets as qt has an stack for changes or It has to be implemented from the very beginn…

---

## [Feed correctly SetHandlePosition for vtkSplineRepresentation](https://discourse.vtk.org/t/feed-correctly-sethandleposition-for-vtksplinerepresentation/4052)

<div class="topic-metadata">

**Author:** [@flaviu2](https://discourse.vtk.org/u/flaviu2)\
**Replies:** 8\
**Last updated:** [September 3, 2020, 10:20am UTC](https://discourse.vtk.org/t/feed-correctly-sethandleposition-for-vtksplinerepresentation/4052 "2020-09-03T10:20:57Z")

</div>

How can I feed correctly SetHandlePosition method from vtkSplineRepresentation ? Let say I have just 3 handles. And a vtkVolume with following dimensions: x = 465, y = 367, z = 189 I have tried: vtkSplineRepresentati…

---

## [In VTK, if the transparency of the image is modified, the depth value of the image will also change.](https://discourse.vtk.org/t/in-vtk-if-the-transparency-of-the-image-is-modified-the-depth-value-of-the-image-will-also-change/4102)

<div class="topic-metadata">

**Author:** [@Pandapan](https://discourse.vtk.org/u/Pandapan)\
**Replies:** 12\
**Last updated:** [September 3, 2020, 10:25am UTC](https://discourse.vtk.org/t/in-vtk-if-the-transparency-of-the-image-is-modified-the-depth-value-of-the-image-will-also-change/4102 "2020-09-03T10:25:56Z")

</div>

In VTK, if the transparency of the image is modified, the depth value of the image will also change. Is there any way to keep the depth unchanged?

---

## [VMTK center lines extraction: how to accelerate it and how to extract center lines from small vessel?](https://discourse.vtk.org/t/vmtk-center-lines-extraction-how-to-accelerate-it-and-how-to-extract-center-lines-from-small-vessel/4103)

<div class="topic-metadata">

**Author:** [@NeuZhangQiang](https://discourse.vtk.org/u/NeuZhangQiang)\
**Replies:** 13\
**Last updated:** [September 3, 2020, 9:44am UTC](https://discourse.vtk.org/t/vmtk-center-lines-extraction-how-to-accelerate-it-and-how-to-extract-center-lines-from-small-vessel/4103 "2020-09-03T09:44:28Z")

</div>

VMTK is really a good tool. I am using VMTK to extract center lines from vessel. And I have two questions: Currently, it would cost 8s for one calculation. Is there any method to accelerate it? Can we use gpu in VMTK? …

---

## [Can't enter selection mode in a rendered window](https://discourse.vtk.org/t/cant-enter-selection-mode-in-a-rendered-window/3975)

<div class="topic-metadata">

**Author:** [@beginner](https://discourse.vtk.org/u/beginner)\
**Replies:** 9\
**Last updated:** [September 2, 2020, 9:52pm UTC](https://discourse.vtk.org/t/cant-enter-selection-mode-in-a-rendered-window/3975 "2020-09-02T21:52:12Z")

</div>

Hi everyone! I’m having trouble entering the selection mode in a render window. Do I just click on ‘r’ on my keyboard? I’ve tried that but it doesn’t work. I’m not sure why that is…

---

## [WorldPointPicker: get the right value if you zoom in](https://discourse.vtk.org/t/worldpointpicker-get-the-right-value-if-you-zoom-in/4096)

<div class="topic-metadata">

**Author:** [@tommi](https://discourse.vtk.org/u/tommi)\
**Replies:** 2\
**Last updated:** [September 2, 2020, 11:21am UTC](https://discourse.vtk.org/t/worldpointpicker-get-the-right-value-if-you-zoom-in/4096 "2020-09-02T11:21:14Z")

</div>

I use this example for a WorldPointPicker. It works fine, but if i zoom in, it doesn’t give the correct coordinates. How can i correct this?

---

## [vtkDICOMImageReader (000002633B49FDB0):](https://discourse.vtk.org/t/vtkdicomimagereader-000002633b49fdb0/4122)

<div class="topic-metadata">

**Author:** [@giri\_lakshman](https://discourse.vtk.org/u/giri_lakshman)\
**Replies:** 0\
**Last updated:** [September 2, 2020, 3:47am UTC](https://discourse.vtk.org/t/vtkdicomimagereader-000002633b49fdb0/4122 "2020-09-02T03:47:53Z")

</div>

Hi, I am working on a simple DICOM reader application using Qt framwork. I followed this code: When i try read a DICOM image file, it shows the following error. ERROR: In D:\\VTK\\VTK-9.0.1\\IO\\Image\\vtkDICOMImageRe…

---

## [VTK and QDataStream](https://discourse.vtk.org/t/vtk-and-qdatastream/4098)

<div class="topic-metadata">

**Author:** [@Cesar\_Cherre](https://discourse.vtk.org/u/Cesar_Cherre)\
**Replies:** 1\
**Last updated:** [September 1, 2020, 3:06pm UTC](https://discourse.vtk.org/t/vtk-and-qdatastream/4098 "2020-09-01T15:06:39Z")

</div>

It is possible to put a VTK Poly in a custom struct to save in binary using QDataStream? work with a custom extension .VSprj and need include .obj into my extension

---

## [Cell Center from GetParametricCenter and EvaluateLocation](https://discourse.vtk.org/t/cell-center-from-getparametriccenter-and-evaluatelocation/4108)

<div class="topic-metadata">

**Author:** [@a-jp1](https://discourse.vtk.org/u/a-jp1)\
**Replies:** 6\
**Last updated:** [September 1, 2020, 1:42pm UTC](https://discourse.vtk.org/t/cell-center-from-getparametriccenter-and-evaluatelocation/4108 "2020-09-01T13:42:03Z")

</div>

Hi, I’m looking for the exact (correct) cell centre for cells of a vtkUnstructuredGrid. Exact (correct) in the sense that it would return the same result as a divergence theorem face-based integration around the faces …

---

## [how to show whole object and part of the object in the same time?](https://discourse.vtk.org/t/how-to-show-whole-object-and-part-of-the-object-in-the-same-time/4107)

<div class="topic-metadata">

**Author:** [@YolkandWhite](https://discourse.vtk.org/u/YolkandWhite)\
**Replies:** 1\
**Last updated:** [August 31, 2020, 8:31pm UTC](https://discourse.vtk.org/t/how-to-show-whole-object-and-part-of-the-object-in-the-same-time/4107 "2020-08-31T20:31:14Z")

</div>

Hi I’m new to VTK. I am trying to do 3d volume rendering with 2d stacked images. and what I’m also trying to find out how to visualize the part of it. for example, If I have ave with an stacked apple picture, I want t…

---

## [Deadline for VTK 9.1 RC1 Merge Requests: October 29, 2020](https://discourse.vtk.org/t/deadline-for-vtk-9-1-rc1-merge-requests-october-29-2020/3206)

<div class="topic-metadata">

**Author:** [@TJ\_Corona](https://discourse.vtk.org/u/TJ_Corona)\
**Replies:** 17\
**Last updated:** [August 31, 2020, 4:54pm UTC](https://discourse.vtk.org/t/deadline-for-vtk-9-1-rc1-merge-requests-october-29-2020/3206 "2020-08-31T16:54:13Z")

</div>

To help the VTK community better anticipate VTK’s release schedule, we are posting a feature deadline for the next release cycle of October 29, 2020. We are hopeful that this approach will give the community enough time …

---

## [vtkHexahedron node ordering question](https://discourse.vtk.org/t/vtkhexahedron-node-ordering-question/4111)

<div class="topic-metadata">

**Author:** [@philippeVerney](https://discourse.vtk.org/u/philippeVerney)\
**Replies:** 5\
**Last updated:** [August 31, 2020, 4:27pm UTC](https://discourse.vtk.org/t/vtkhexahedron-node-ordering-question/4111 "2020-08-31T16:27:41Z")

</div>

Hi all, I am looking at VTK conventions for node ordering especially for vtkHexahedron. I am also looking at the VTK documentation stating : The hexahedron is defined by the eight points (0-7) where (0,1,2,3) is the ba…

---

## [Interactive text widget. Search box.](https://discourse.vtk.org/t/interactive-text-widget-search-box/4009)

<div class="topic-metadata">

**Author:** [@phcerdan](https://discourse.vtk.org/u/phcerdan)\
**Replies:** 5\
**Last updated:** [August 31, 2020, 11:31am UTC](https://discourse.vtk.org/t/interactive-text-widget-search-box/4009 "2020-08-31T11:31:06Z")

</div>

I’d like to have a search box in my scene, where the user enters a point id, and that point is highlighted for example. Is there any widget that handles the input of text from the user? I am guessing that a TextWidget c…

---

## [VMTK：question about the input of vtkvmtkPolyDataCenterlines](https://discourse.vtk.org/t/vmtk-question-about-the-input-of-vtkvmtkpolydatacenterlines/4088)

<div class="topic-metadata">

**Author:** [@NeuZhangQiang](https://discourse.vtk.org/u/NeuZhangQiang)\
**Replies:** 1\
**Last updated:** [August 31, 2020, 8:23am UTC](https://discourse.vtk.org/t/vmtk-question-about-the-input-of-vtkvmtkpolydatacenterlines/4088 "2020-08-31T08:23:57Z")

</div>

I need to extract center lines from airway mask, and VMTK is a very good tool. VMTK use vtkvmtkPolyDataCenterlines to extract the center lines, and the usage of vtkvmtkPolyDataCenterlines is: centerlineFilter = vtk…

---

## [Issue with using vtkPythonUtil::GetObjectFromPointer for custom VTK classes](https://discourse.vtk.org/t/issue-with-using-vtkpythonutil-getobjectfrompointer-for-custom-vtk-classes/4100)

<div class="topic-metadata">

**Author:** [@jcfr](https://discourse.vtk.org/u/jcfr)\
**Replies:** 10\
**Last updated:** [August 29, 2020, 8:56pm UTC](https://discourse.vtk.org/t/issue-with-using-vtkpythonutil-getobjectfrompointer-for-custom-vtk-classes/4100 "2020-08-29T20:56:05Z")

</div>

Working on updating Slicer to build against the latest VTK (see \[1\]), I noticed that VTK object returned by Qt slots only include vtkObject methods. Question: While I am investigating further, does anyone have ideas on…

---

## [Scale bars in vtk python](https://discourse.vtk.org/t/scale-bars-in-vtk-python/4094)

<div class="topic-metadata">

**Author:** [@Olga\_Ridzel](https://discourse.vtk.org/u/Olga_Ridzel)\
**Replies:** 3\
**Last updated:** [August 29, 2020, 4:13pm UTC](https://discourse.vtk.org/t/scale-bars-in-vtk-python/4094 "2020-08-29T16:13:22Z")

</div>

Dear VTK team, I’m looking for a way to add scale bars to the render window both in python and js. An example picture is attached. I used vtkLineSource and vtkVectorText but depending on the image size I render this do…

---

## [vtk, SimpleITK and blender](https://discourse.vtk.org/t/vtk-simpleitk-and-blender/4093)

<div class="topic-metadata">

**Author:** [@Issam\_Dak](https://discourse.vtk.org/u/Issam_Dak)\
**Replies:** 0\
**Last updated:** [August 28, 2020, 2:35pm UTC](https://discourse.vtk.org/t/vtk-simpleitk-and-blender/4093 "2020-08-28T14:35:24Z")

</div>

Hi, i m new to vtk and SimpleITK and i need some help. I m trying to make a blender addon for reading NRRD file exported from 3Dslicer or dicom sequence from user directory The volume will be read using vtk NRRD reader…

---

## [\[vtk.js\]How to apply imagestreamlines linewidth](https://discourse.vtk.org/t/vtk-js-how-to-apply-imagestreamlines-linewidth/4074)

<div class="topic-metadata">

**Author:** [@1118](https://discourse.vtk.org/u/1118)\
**Replies:** 4\
**Last updated:** [August 28, 2020, 1:57pm UTC](https://discourse.vtk.org/t/vtk-js-how-to-apply-imagestreamlines-linewidth/4074 "2020-08-28T13:57:59Z")

</div>

Hello I have been trying to implement “Stream Lines Presentation plugin”(https://blog.kitware.com/new-animated-stream-lines-representation-for-paraview-5-3/) in Paraview as vtk.js, so I have been looking at Imagestreaml…

---

## [How to crop 3D image from a 2D free-hand ROI?](https://discourse.vtk.org/t/how-to-crop-3d-image-from-a-2d-free-hand-roi/2468)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 6\
**Last updated:** [August 28, 2020, 5:58am UTC](https://discourse.vtk.org/t/how-to-crop-3d-image-from-a-2d-free-hand-roi/2468 "2020-08-28T05:58:33Z")

</div>

When analysis 3D image data by rendering, some tissue is unconcerned and it would distrub the analysis. Thus, I want to crop the image by a free-hand ROI just like RadiAnt: In the above picture, the green polygon is t…

---

## [Attribute data for cell faces of an Unstructured Grid](https://discourse.vtk.org/t/attribute-data-for-cell-faces-of-an-unstructured-grid/4086)

<div class="topic-metadata">

**Author:** [@mdh](https://discourse.vtk.org/u/mdh)\
**Replies:** 0\
**Last updated:** [August 27, 2020, 8:24pm UTC](https://discourse.vtk.org/t/attribute-data-for-cell-faces-of-an-unstructured-grid/4086 "2020-08-27T20:24:34Z")

</div>

Is there a way to add attribute data to faces of an unstructured grid? I’m trying to solve a problem where I want to add ids to each face of every cell in an unstructured grid and then get the polygonal surfaces from th…

---

## [Adding extra padding to a nifti image](https://discourse.vtk.org/t/adding-extra-padding-to-a-nifti-image/4038)

<div class="topic-metadata">

**Author:** [@isuruwi](https://discourse.vtk.org/u/isuruwi)\
**Replies:** 3\
**Last updated:** [August 27, 2020, 8:53am UTC](https://discourse.vtk.org/t/adding-extra-padding-to-a-nifti-image/4038 "2020-08-27T08:53:48Z")

</div>

I have a nifiti image where the dimension is (200, 200, 320) and what I want to do is that increase the height and width of the image by adding additional padding around it so that finally it contains (512, 512, 320). Is…

---

## [Help with building Paraview Glance](https://discourse.vtk.org/t/help-with-building-paraview-glance/4075)

<div class="topic-metadata">

**Author:** [@Ramu](https://discourse.vtk.org/u/Ramu)\
**Replies:** 4\
**Last updated:** [August 27, 2020, 6:28am UTC](https://discourse.vtk.org/t/help-with-building-paraview-glance/4075 "2020-08-27T06:28:30Z")

</div>

Hello I am trying to build paraview-glance from Kitware/ paraview-glance GitHub repo. It was successful on my personal laptop but unable to do so in my office machine. (I use enterprise registry and they prevent download…

---

## [Add temperature attribute using vtkDoubleArray-\>SetArray is not effect the result color](https://discourse.vtk.org/t/add-temperature-attribute-using-vtkdoublearray-setarray-is-not-effect-the-result-color/4045)

<div class="topic-metadata">

**Author:** [@wanddfly](https://discourse.vtk.org/u/wanddfly)\
**Replies:** 10\
**Last updated:** [August 26, 2020, 10:47pm UTC](https://discourse.vtk.org/t/add-temperature-attribute-using-vtkdoublearray-setarray-is-not-effect-the-result-color/4045 "2020-08-26T22:47:15Z")

</div>

Hi, I am a beginner, when I my vtkUnstructuredGrid object have a attribute temperature, there are 2 methods to put it into vtkUnstructuredGrid object, one is that put 1 by 1 using InsertNextTuple1() , this method work …

---

## [vtkPolyDataAlgorithm: how does Update() deal with return value of RequestData()?](https://discourse.vtk.org/t/vtkpolydataalgorithm-how-does-update-deal-with-return-value-of-requestdata/4070)

<div class="topic-metadata">

**Author:** [@Tomasso](https://discourse.vtk.org/u/Tomasso)\
**Replies:** 1\
**Last updated:** [August 26, 2020, 9:01pm UTC](https://discourse.vtk.org/t/vtkpolydataalgorithm-how-does-update-deal-with-return-value-of-requestdata/4070 "2020-08-26T21:01:11Z")

</div>

void vtkPolyDataAlgorithm::Update() calls virtual int vtkPolyDataAlgorithm::RequestData(). MyAlgorithm is a subclass of vtkPolyDataAlgorithm, and overrides virtual int vtkPolyDataAlgorithm::RequestData(). But the Doxygen …

---

## [Volume Rendering With VTK WebAssembly](https://discourse.vtk.org/t/volume-rendering-with-vtk-webassembly/4077)

<div class="topic-metadata">

**Author:** [@Donny\_Zimmerman](https://discourse.vtk.org/u/Donny_Zimmerman)\
**Replies:** 3\
**Last updated:** [August 26, 2020, 3:06pm UTC](https://discourse.vtk.org/t/volume-rendering-with-vtk-webassembly/4077 "2020-08-26T15:06:46Z")

</div>

I first want to say I appreciate all the work that has been done to be able to generate WebAssembly for browsers using VTK. My question is if there is ongoing work to get volume rendering working with WebAssembly? I know…

---

## [framebuffer has mismatched attachments error when using vtkSobelGradientMagnitudePass and resizing window](https://discourse.vtk.org/t/framebuffer-has-mismatched-attachments-error-when-using-vtksobelgradientmagnitudepass-and-resizing-window/4073)

<div class="topic-metadata">

**Author:** [@rdbrn](https://discourse.vtk.org/u/rdbrn)\
**Replies:** 1\
**Last updated:** [August 26, 2020, 8:56am UTC](https://discourse.vtk.org/t/framebuffer-has-mismatched-attachments-error-when-using-vtksobelgradientmagnitudepass-and-resizing-window/4073 "2020-08-26T08:56:17Z")

</div>

I’m playing a bit with a vtkSobelGradientMagnitudePass pass using python and vtk 9.0.1 on Windows 10. When I resize my window I get the following error: “ERROR: In …\\Rendering\\OpenGL2\\vtkOpenGLFramebufferObject.cxx, …

---

## [In parallel environment, can VTK remove the background of rendering?](https://discourse.vtk.org/t/in-parallel-environment-can-vtk-remove-the-background-of-rendering/4034)

<div class="topic-metadata">

**Author:** [@Pandapan](https://discourse.vtk.org/u/Pandapan)\
**Replies:** 5\
**Last updated:** [August 26, 2020, 6:44am UTC](https://discourse.vtk.org/t/in-parallel-environment-can-vtk-remove-the-background-of-rendering/4034 "2020-08-26T06:44:27Z")

</div>

I am trying to using VTK for parallel rendering. The problem is that the background will cause errors during image composition. For example, I use two processes to render two images (A and B), respectively. When these…

---

## [\[vtk.js\] Add logo to render view](https://discourse.vtk.org/t/vtk-js-add-logo-to-render-view/4068)

<div class="topic-metadata">

**Author:** [@banesullivan](https://discourse.vtk.org/u/banesullivan)\
**Replies:** 6\
**Last updated:** [August 25, 2020, 5:45pm UTC](https://discourse.vtk.org/t/vtk-js-add-logo-to-render-view/4068 "2020-08-25T17:45:42Z")

</div>

I’m curious if there is an easy way to add a logo/icon to the top right of the vtk.js render window. Would I do something like (I’m not getting this to work): ... import style from './controller.css'; import icon from…

---

## [Vtk.js, VTP Volume Rendering](https://discourse.vtk.org/t/vtk-js-vtp-volume-rendering/4064)

<div class="topic-metadata">

**Author:** [@samm-vs](https://discourse.vtk.org/u/samm-vs)\
**Replies:** 3\
**Last updated:** [August 25, 2020, 4:33pm UTC](https://discourse.vtk.org/t/vtk-js-vtp-volume-rendering/4064 "2020-08-25T16:33:41Z")

</div>

Does Vtk.js support volume rendering/ volume contours from vtp files? If it can’t are there any workaround for it? I have data that is in a vtp format and I would like to do the same things with it as if they were vti fi…

---

## [Show directed AND undirected edges on vtkGraphLayoutView](https://discourse.vtk.org/t/show-directed-and-undirected-edges-on-vtkgraphlayoutview/4062)

<div class="topic-metadata">

**Author:** [@Andreas\_Scalas](https://discourse.vtk.org/u/Andreas_Scalas)\
**Replies:** 0\
**Last updated:** [August 24, 2020, 6:18pm UTC](https://discourse.vtk.org/t/show-directed-and-undirected-edges-on-vtkgraphlayoutview/4062 "2020-08-24T18:18:19Z")

</div>

Hello, I am new to the VTK support forum. If possible, I would like to ask if any of you have ever tried to display a graph with both directed and undirected edges using the vtkGraphLayoutView class. I came out with the …

[Previous page](https://discourse.vtk.org/latest.md?page=200)

[Next page](https://discourse.vtk.org/latest.md?page=202)