# Latest

**URL:** https://discourse.vtk.org/latest.md?page=213

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

**Page:** 214

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## [How to convert vtkimagedata of vtk.js to opencv.js Mat](https://discourse.vtk.org/t/how-to-convert-vtkimagedata-of-vtk-js-to-opencv-js-mat/3330)

<div class="topic-metadata">

**Author:** [@huatianyu](https://discourse.vtk.org/u/huatianyu)\
**Replies:** 0\
**Last updated:** [May 19, 2020, 2:44am UTC](https://discourse.vtk.org/t/how-to-convert-vtkimagedata-of-vtk-js-to-opencv-js-mat/3330 "2020-05-19T02:44:45Z")

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Like C++: // vtkImageData==\>Mat cv::Mat vtkImage2Mat(vtkImageData \*image) { int dim\[3\]; image-\>GetDimensions(dim); int imgType=CV\_8UC1; if(image-\>GetNumberOfScalarComponents()==1) imgType=CV\_8UC1; if(image-\>Get…

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## [Can I specify the value that vtkImageReslice pads output images with (instead of zero)?](https://discourse.vtk.org/t/can-i-specify-the-value-that-vtkimagereslice-pads-output-images-with-instead-of-zero/3324)

<div class="topic-metadata">

**Author:** [@MichelleKline](https://discourse.vtk.org/u/MichelleKline)\
**Replies:** 2\
**Last updated:** [May 18, 2020, 3:26pm UTC](https://discourse.vtk.org/t/can-i-specify-the-value-that-vtkimagereslice-pads-output-images-with-instead-of-zero/3324 "2020-05-18T15:26:28Z")

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Hello, When the vtkImageReslice attribute AutoCropOutput is set to “on”, the output images are either cropped or enlarged by padding. When the output image is padded, vtkImageReslice pads with zeros. Can I control the…

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## [Nifti to vtkImageData in memory](https://discourse.vtk.org/t/nifti-to-vtkimagedata-in-memory/3302)

<div class="topic-metadata">

**Author:** [@rijobro](https://discourse.vtk.org/u/rijobro)\
**Replies:** 18\
**Last updated:** [May 18, 2020, 2:33pm UTC](https://discourse.vtk.org/t/nifti-to-vtkimagedata-in-memory/3302 "2020-05-18T14:33:34Z")

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I have a 4D nifti\_image, representing a displacement field image. I would like to get the inverse using vtkGridTransform, which implies that I need to convert my nifti\_image to a vtkImageData. Is there the functionality…

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## [GL2PS Exporter and text justification](https://discourse.vtk.org/t/gl2ps-exporter-and-text-justification/3322)

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**Author:** [@Nicolas\_Lenoir](https://discourse.vtk.org/u/Nicolas_Lenoir)\
**Replies:** 0\
**Last updated:** [May 18, 2020, 7:51am UTC](https://discourse.vtk.org/t/gl2ps-exporter-and-text-justification/3322 "2020-05-18T07:51:03Z")

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Hello , I post this topic because I have a problem with the export of vtkCaptionActor2D with the vtkGL2PSExporter, when I center the text in the boxes, when i export the render window the text is not justify and go out o…

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## [where are the model files of vtk examples](https://discourse.vtk.org/t/where-are-the-model-files-of-vtk-examples/3321)

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**Author:** [@xuexl](https://discourse.vtk.org/u/xuexl)\
**Replies:** 2\
**Last updated:** [May 18, 2020, 6:42am UTC](https://discourse.vtk.org/t/where-are-the-model-files-of-vtk-examples/3321 "2020-05-18T06:42:00Z")

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Some vtk example need model files, e.g., StreamLines , it needs “xyzFile” and “qFile” , where are these files ? Can i download from any place? anybody know this ? Thank you.

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## [VTK CMake Usage](https://discourse.vtk.org/t/vtk-cmake-usage/3275)

<div class="topic-metadata">

**Author:** [@webbbn](https://discourse.vtk.org/u/webbbn)\
**Replies:** 8\
**Last updated:** [May 17, 2020, 9:58pm UTC](https://discourse.vtk.org/t/vtk-cmake-usage/3275 "2020-05-17T21:58:56Z")

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How does one find and use VTK in CMake with 9.0.0. I’m using find\_package(VTK REQUIRED …), and it’s seems happy, although the only output appears to be finding X11 and Xt. All the documentation that I can find is conflic…

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## [Jacobian of B-spline coefficients](https://discourse.vtk.org/t/jacobian-of-b-spline-coefficients/3310)

<div class="topic-metadata">

**Author:** [@rijobro](https://discourse.vtk.org/u/rijobro)\
**Replies:** 4\
**Last updated:** [May 16, 2020, 10:52pm UTC](https://discourse.vtk.org/t/jacobian-of-b-spline-coefficients/3310 "2020-05-16T22:52:39Z")

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For a motion-estimation algorithm, we’d like to be able to calculate the Jacboian of b-spline coefficients. Alternatively (and less computationally expensive), we’d like to be able to apply this Jacboian onto a pre-exist…

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## [Remove 3 elements from vtkStringArray](https://discourse.vtk.org/t/remove-3-elements-from-vtkstringarray/3317)

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**Author:** [@flaviu2](https://discourse.vtk.org/u/flaviu2)\
**Replies:** 2\
**Last updated:** [May 16, 2020, 10:34pm UTC](https://discourse.vtk.org/t/remove-3-elements-from-vtkstringarray/3317 "2020-05-16T22:34:31Z")

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Is there any way to remove 3 elements from a vtkStringArray without clean up the array and load all elements except those 3 ? And, how can I delete all elements from array without Delete method and create another one ? …

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## [VTK9.0.0 : manage nrrd with gzip compression ?](https://discourse.vtk.org/t/vtk9-0-0-manage-nrrd-with-gzip-compression/3252)

<div class="topic-metadata">

**Author:** [@TheRalph](https://discourse.vtk.org/u/TheRalph)\
**Replies:** 2\
**Last updated:** [May 16, 2020, 9:18am UTC](https://discourse.vtk.org/t/vtk9-0-0-manage-nrrd-with-gzip-compression/3252 "2020-05-16T09:18:48Z")

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Hi, I need to open nrrd file using gzip compression. I saw that feature had been integrated in master with commit cb7027c7c53 on Mon Apr 6 2020 which is great. Unfortunately it is not integrated in v9.0.0, do you know …

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## [deal vtk data (such as vtkimagedata) in a qthread, app.exe crushed.](https://discourse.vtk.org/t/deal-vtk-data-such-as-vtkimagedata-in-a-qthread-app-exe-crushed/3313)

<div class="topic-metadata">

**Author:** [@xiangyang](https://discourse.vtk.org/u/xiangyang)\
**Replies:** 0\
**Last updated:** [May 15, 2020, 8:40am UTC](https://discourse.vtk.org/t/deal-vtk-data-such-as-vtkimagedata-in-a-qthread-app-exe-crushed/3313 "2020-05-15T08:40:39Z")

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such as, define a vtkimagedata in main thread, then , getscalarpoint int another qthread. when exit the qthread, exe crushed!

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## [VTK + PDAL for LIDAR data reading. Error with build](https://discourse.vtk.org/t/vtk-pdal-for-lidar-data-reading-error-with-build/3305)

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**Author:** [@Oscar](https://discourse.vtk.org/u/Oscar)\
**Replies:** 3\
**Last updated:** [May 14, 2020, 9:59pm UTC](https://discourse.vtk.org/t/vtk-pdal-for-lidar-data-reading-error-with-build/3305 "2020-05-14T21:59:23Z")

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Hello everyone, I’m trying to build VTK with the PDAL module and it seems that I’m doing something wrong. I downloaded and installed pdal through miniconda and set the PDAL\_DIR on CMake when building vtk. But the PDAL …

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## [VTK 9 + Java on Mac](https://discourse.vtk.org/t/vtk-9-java-on-mac/3250)

<div class="topic-metadata">

**Author:** [@Marco](https://discourse.vtk.org/u/Marco)\
**Replies:** 41\
**Last updated:** [May 14, 2020, 2:45pm UTC](https://discourse.vtk.org/t/vtk-9-java-on-mac/3250 "2020-05-14T14:45:24Z")

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Hello. I am trying to build VTK 9.0 with Java bindings on macOS 10.15.4 (latest). I am aware that there is a similar discussion on the “Development” forum (https://discourse.vtk.org/t/problem-with-java-bindings-in-vtk-…

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## [Numpy to vtk](https://discourse.vtk.org/t/numpy-to-vtk/3306)

<div class="topic-metadata">

**Author:** [@RomyM](https://discourse.vtk.org/u/RomyM)\
**Replies:** 0\
**Last updated:** [May 14, 2020, 2:15pm UTC](https://discourse.vtk.org/t/numpy-to-vtk/3306 "2020-05-14T14:15:41Z")

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Hello, I am able to visualize a volume in vtk of a 3D image using the mask function and volume rendering. I do have two visualizations: Correct visualized: Original image and binary masked image of expert (both import…

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## [vtkOSPRayPass in Python](https://discourse.vtk.org/t/vtkospraypass-in-python/3304)

<div class="topic-metadata">

**Author:** [@akaszynski](https://discourse.vtk.org/u/akaszynski)\
**Replies:** 1\
**Last updated:** [May 14, 2020, 12:36pm UTC](https://discourse.vtk.org/t/vtkospraypass-in-python/3304 "2020-05-14T12:36:52Z")

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Hello, It would appear that there’s no support for vtkOSPRayPass in the latest vtk 9.0.0 Python wheel. Is there any plan to support it? Thanks for all your hard work!

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## [VTK 9 Release Notes](https://discourse.vtk.org/t/vtk-9-release-notes/3290)

<div class="topic-metadata">

**Author:** [@sherinnovation](https://discourse.vtk.org/u/sherinnovation)\
**Replies:** 4\
**Last updated:** [May 14, 2020, 12:14pm UTC](https://discourse.vtk.org/t/vtk-9-release-notes/3290 "2020-05-14T12:14:40Z")

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Hi, I am trying to understand what has been newly introduced in VTK 9 when compared with previous verions. How can I get this information? Unfortunately, I couldn’t find anything like release notes. Please help. Thanks …

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## [consuming much memory when the model runs](https://discourse.vtk.org/t/consuming-much-memory-when-the-model-runs/2901)

<div class="topic-metadata">

**Author:** [@xuexl](https://discourse.vtk.org/u/xuexl)\
**Replies:** 8\
**Last updated:** [May 14, 2020, 11:59am UTC](https://discourse.vtk.org/t/consuming-much-memory-when-the-model-runs/2901 "2020-05-14T11:59:46Z")

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I encounter a strange question, when the model runs, the memory of my computer is consumed so much, about ten times or more of the model size. Has anyone encountered the same problem ? Waiting for your anwser, welcome…

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## [Question about face numbering in hexahedron cells](https://discourse.vtk.org/t/question-about-face-numbering-in-hexahedron-cells/3286)

<div class="topic-metadata">

**Author:** [@lijas](https://discourse.vtk.org/u/lijas)\
**Replies:** 1\
**Last updated:** [May 14, 2020, 9:26am UTC](https://discourse.vtk.org/t/question-about-face-numbering-in-hexahedron-cells/3286 "2020-05-14T09:26:29Z")

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For the cell vtkTriQuadraticHexahedron, the face numbering is defined here as The mid-surface nodes lies on the faces defined by (first edge nodes id’s, than mid-edge nodes id’s): (0,1,5,4;8,17,12,16), (1,2,6,5;9,18,13…

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## [Faster method for GetPoint](https://discourse.vtk.org/t/faster-method-for-getpoint/3189)

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**Author:** [@Ron84](https://discourse.vtk.org/u/Ron84)\
**Replies:** 19\
**Last updated:** [May 13, 2020, 6:34pm UTC](https://discourse.vtk.org/t/faster-method-for-getpoint/3189 "2020-05-13T18:34:45Z")

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I figured out that doing this costs a lot time for many calls: double ptA\[3\], ptB\[3\]; pd-\>GetPoint(poly\[i\], ptA); pd-\>GetPoint(poly\[j\], ptB); Is there a more direct method without copying? This does not work, because…

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## [access vtkSmartPointer member variable](https://discourse.vtk.org/t/access-vtksmartpointer-member-variable/3269)

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**Author:** [@rds15](https://discourse.vtk.org/u/rds15)\
**Replies:** 6\
**Last updated:** [May 13, 2020, 3:19am UTC](https://discourse.vtk.org/t/access-vtksmartpointer-member-variable/3269 "2020-05-13T03:19:16Z")

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Hi All, I have a question regarding proper use of vtkSmartPointer as a member variable. As I understand it, to prevent the smart pointer from going out of scope, it can be set as a member variable so that it is not dele…

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## [About vtkRenderWindowInteractor](https://discourse.vtk.org/t/about-vtkrenderwindowinteractor/3294)

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**Author:** [@Seram](https://discourse.vtk.org/u/Seram)\
**Replies:** 0\
**Last updated:** [May 13, 2020, 2:56am UTC](https://discourse.vtk.org/t/about-vtkrenderwindowinteractor/3294 "2020-05-13T02:56:58Z")

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Hello everyone I succeeded in viewing Ply 3D Data. But I would like to disable the actor’s rotation (= left mouse click) function among the many functions of vtkRenderWindowInteractor. I would appreciate it if you cou…

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## [How to get the position of image in the vtkimageviewer2](https://discourse.vtk.org/t/how-to-get-the-position-of-image-in-the-vtkimageviewer2/3291)

<div class="topic-metadata">

**Author:** [@Amnesie](https://discourse.vtk.org/u/Amnesie)\
**Replies:** 0\
**Last updated:** [May 13, 2020, 12:56am UTC](https://discourse.vtk.org/t/how-to-get-the-position-of-image-in-the-vtkimageviewer2/3291 "2020-05-13T00:56:31Z")

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Hello everyone, I have a new problem with vtk when i try to get the position of image in the vtkimageviewer2 if i clicked left button. I set a dicomseries as Input to vtkimageviewer2 ,it works fine Here is my Code,I o…

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## [How to use vtkTemporalStatistics?](https://discourse.vtk.org/t/how-to-use-vtktemporalstatistics/3289)

<div class="topic-metadata">

**Author:** [@myousefi2016](https://discourse.vtk.org/u/myousefi2016)\
**Replies:** 0\
**Last updated:** [May 12, 2020, 8:40pm UTC](https://discourse.vtk.org/t/how-to-use-vtktemporalstatistics/3289 "2020-05-12T20:40:54Z")

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I’m trying to use vtkTemporalStatistics in python. Basically I have several vtkUnstructuredGrid objects and I want to feed them into vtkTemporalStatistics to take time-average over them. I’m not sure how to feed each tim…

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## [Differences in paraview and vtk volume rendering?](https://discourse.vtk.org/t/differences-in-paraview-and-vtk-volume-rendering/3288)

<div class="topic-metadata">

**Author:** [@kevins](https://discourse.vtk.org/u/kevins)\
**Replies:** 1\
**Last updated:** [May 12, 2020, 8:30pm UTC](https://discourse.vtk.org/t/differences-in-paraview-and-vtk-volume-rendering/3288 "2020-05-12T20:30:25Z")

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I am trying to create a volume rendering in vtk that resembles the paraview output as closely as possible. Is it possible to produce the same volume rendering with paraview and vtk? Are there known settings or pipeline…

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## [VTK9: Problem with display helper object factory](https://discourse.vtk.org/t/vtk9-problem-with-display-helper-object-factory/3287)

<div class="topic-metadata">

**Author:** [@codeling](https://discourse.vtk.org/u/codeling)\
**Replies:** 2\
**Last updated:** [May 12, 2020, 7:39pm UTC](https://discourse.vtk.org/t/vtk9-problem-with-display-helper-object-factory/3287 "2020-05-12T19:39:16Z")

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Trying to build and run our application against VTK 9, I’m running into the trouble that when we create our 3D volume rendering pipeline, it crashes on line 647 of vtkFixedPointVolumeRayCastMapper.cxx (apparently there i…

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## [How should the xml file for bezier geometries look like?](https://discourse.vtk.org/t/how-should-the-xml-file-for-bezier-geometries-look-like/3235)

<div class="topic-metadata">

**Author:** [@lijas](https://discourse.vtk.org/u/lijas)\
**Replies:** 3\
**Last updated:** [May 12, 2020, 5:41pm UTC](https://discourse.vtk.org/t/how-should-the-xml-file-for-bezier-geometries-look-like/3235 "2020-05-12T17:41:11Z")

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Hello In my FE program i want to export some beizer cells so I can visualize them in paraview. I cant find any documentation on how the cells/points/weights of the bezier cells should exported. I am completely new to …

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## [Segmentation fault with a SIGSEGV signal](https://discourse.vtk.org/t/segmentation-fault-with-a-sigsegv-signal/3277)

<div class="topic-metadata">

**Author:** [@davidlni](https://discourse.vtk.org/u/davidlni)\
**Replies:** 5\
**Last updated:** [May 12, 2020, 4:38pm UTC](https://discourse.vtk.org/t/segmentation-fault-with-a-sigsegv-signal/3277 "2020-05-12T16:38:00Z")

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Hi all, I built VTK from source on my docker Ubuntu container. If I run any Python script which involves renderer, I get following segmentation fault error. In CCMake, I did turn on RenderingOpenGL2 and the corresponded…

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## [Windows rendering issues](https://discourse.vtk.org/t/windows-rendering-issues/2542)

<div class="topic-metadata">

**Author:** [@Gilthalas](https://discourse.vtk.org/u/Gilthalas)\
**Replies:** 18\
**Last updated:** [May 12, 2020, 3:28pm UTC](https://discourse.vtk.org/t/windows-rendering-issues/2542 "2020-05-12T15:28:54Z")

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OK, seeing some odd behaviors on Window using Java/VTK 6.3 (but also with 8.1.2 as well). In a vtkCaptionActor2D caption, the degree symbol (0x00B0) does NOT render, and it actually will cause the ENTIRE caption text t…

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## [Input arrays with vtkPythonAlgorithm](https://discourse.vtk.org/t/input-arrays-with-vtkpythonalgorithm/3282)

<div class="topic-metadata">

**Author:** [@lhofmann](https://discourse.vtk.org/u/lhofmann)\
**Replies:** 0\
**Last updated:** [May 12, 2020, 11:28am UTC](https://discourse.vtk.org/t/input-arrays-with-vtkpythonalgorithm/3282 "2020-05-12T11:28:31Z")

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Python classes derived from VTKPythonAlgorithmBase have the usual SetInputArrayToProcess method but no GetInputArrayToProcess. However, GetInputArrayInformation does exist and works just like in C++. Ist this done on pu…

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## [Plane size limitations?](https://discourse.vtk.org/t/plane-size-limitations/3280)

<div class="topic-metadata">

**Author:** [@Yongun\_Lee](https://discourse.vtk.org/u/Yongun_Lee)\
**Replies:** 0\
**Last updated:** [May 12, 2020, 10:58am UTC](https://discourse.vtk.org/t/plane-size-limitations/3280 "2020-05-12T10:58:02Z")

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Hello. When we arrive at the edge of the plane, we do not want the plane to be widened. (Indicated in blue.) What should I do?

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## [Segfault on VTK 9.0.0 when creating vtkTextActor](https://discourse.vtk.org/t/segfault-on-vtk-9-0-0-when-creating-vtktextactor/3265)

<div class="topic-metadata">

**Author:** [@olympionex](https://discourse.vtk.org/u/olympionex)\
**Replies:** 4\
**Last updated:** [May 12, 2020, 5:14am UTC](https://discourse.vtk.org/t/segfault-on-vtk-9-0-0-when-creating-vtktextactor/3265 "2020-05-12T05:14:35Z")

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On line 78 of vtkTextActor.cxx, the call to vtkTexture::New() returns a nullptr seemingly because it can’t find a factory to create that type and then I get a segfault when the next line tries to deference that pointer. …

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