# Latest

**URL:** https://discourse.vtk.org/latest.md?page=191

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

**Page:** 192

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## [How to disable the low pass filter effect on vtkImageViewer2?](https://discourse.vtk.org/t/how-to-disable-the-low-pass-filter-effect-on-vtkimageviewer2/4759)

<div class="topic-metadata">

**Author:** [@Kim\_William](https://discourse.vtk.org/u/Kim_William)\
**Replies:** 2\
**Last updated:** [December 2, 2020, 1:16am UTC](https://discourse.vtk.org/t/how-to-disable-the-low-pass-filter-effect-on-vtkimageviewer2/4759 "2020-12-02T01:16:04Z")

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Hi all :slight\_smile: I have a question about vtkImageViewer2. I have tested loading and drawing an image with the sample code. Link: https://lorensen.github.io/VTKExamples/site/Cxx/Images/StaticImage/ It works well …

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## [Intersection of 3D mesh with polydata (return only intersecting mesh region)](https://discourse.vtk.org/t/intersection-of-3d-mesh-with-polydata-return-only-intersecting-mesh-region/4747)

<div class="topic-metadata">

**Author:** [@kradan](https://discourse.vtk.org/u/kradan)\
**Replies:** 3\
**Last updated:** [December 1, 2020, 7:13am UTC](https://discourse.vtk.org/t/intersection-of-3d-mesh-with-polydata-return-only-intersecting-mesh-region/4747 "2020-12-01T07:13:02Z")

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Hi, I would appreciate your help with a problem related to finding object intersections. I have a vtkMesh (.vtk, a brain edema), and vtkPolyData (.vtk, diffusion MRI tractography streamlines), and I want to obtain only t…

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## [How to test if two STL files intersect?](https://discourse.vtk.org/t/how-to-test-if-two-stl-files-intersect/4742)

<div class="topic-metadata">

**Author:** [@sally0226](https://discourse.vtk.org/u/sally0226)\
**Replies:** 4\
**Last updated:** [December 1, 2020, 3:17am UTC](https://discourse.vtk.org/t/how-to-test-if-two-stl-files-intersect/4742 "2020-12-01T03:17:51Z")

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I want to get intersection between two stl files so I use vtkBooleanOperationPolyDataFilter, but it didn’t work well. usually cases work well, but some cases have error this is my code reader1 = vtk.vtkSTLReader() re…

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## [Clipping by Scalar from CellData / vtkClipDataSet / Python](https://discourse.vtk.org/t/clipping-by-scalar-from-celldata-vtkclipdataset-python/4724)

<div class="topic-metadata">

**Author:** [@Jason1](https://discourse.vtk.org/u/Jason1)\
**Replies:** 2\
**Last updated:** [November 30, 2020, 10:07am UTC](https://discourse.vtk.org/t/clipping-by-scalar-from-celldata-vtkclipdataset-python/4724 "2020-11-30T10:07:13Z")

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Hello, I want to read a .vtu file and clip it so that I can work with the necessary data only. To do so the .vtu contains CellData with a tag which I can use to clip by scalars. After some searching I came to the follow…

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## [How about interactor using](https://discourse.vtk.org/t/how-about-interactor-using/4730)

<div class="topic-metadata">

**Author:** [@DL\_men](https://discourse.vtk.org/u/DL_men)\
**Replies:** 5\
**Last updated:** [November 30, 2020, 1:14am UTC](https://discourse.vtk.org/t/how-about-interactor-using/4730 "2020-11-30T01:14:26Z")

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vtk.vtkInteractorStyleRubberBandPick This interactor style allows the user to draw a rectangle in the render window by hitting ‘r’ .How can I do event(draw a rectangle) withou hitting ‘r’?

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## [Link server side camera to local problems](https://discourse.vtk.org/t/link-server-side-camera-to-local-problems/4749)

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**Author:** [@Francesc](https://discourse.vtk.org/u/Francesc)\
**Replies:** 1\
**Last updated:** [November 29, 2020, 12:34pm UTC](https://discourse.vtk.org/t/link-server-side-camera-to-local-problems/4749 "2020-11-29T12:34:25Z")

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Hello, I am building an angular app. I am learning about it and using Paraview Lite as a reference. I am building it in Angular because I have more experience in Angular than in Vue. I reach a point which most of it s…

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## [vtkCollection... am I using it well?](https://discourse.vtk.org/t/vtkcollection-am-i-using-it-well/4732)

<div class="topic-metadata">

**Author:** [@bistek](https://discourse.vtk.org/u/bistek)\
**Replies:** 11\
**Last updated:** [November 28, 2020, 2:51pm UTC](https://discourse.vtk.org/t/vtkcollection-am-i-using-it-well/4732 "2020-11-28T14:51:50Z")

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Hello, I have a Python project where I use (visualize, model, interpolate, etc.) several VTK objects at the same time, including polydata, images, structured grids, etc. At the moment I am collecting all these objects i…

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## [Generate surface mesh from label mask image volume](https://discourse.vtk.org/t/generate-surface-mesh-from-label-mask-image-volume/4720)

<div class="topic-metadata">

**Author:** [@isuruwi](https://discourse.vtk.org/u/isuruwi)\
**Replies:** 2\
**Last updated:** [November 28, 2020, 2:38am UTC](https://discourse.vtk.org/t/generate-surface-mesh-from-label-mask-image-volume/4720 "2020-11-28T02:38:19Z")

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I have generated a segmentation mask for a CT volume and and saved it as a nifti format. This image volume consists of below set of categories. 0: Background (None of the following organs) 1: Liver 2: Bladder 3: Lung…

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## [vtkPolyDataConnectivityFilter reverse](https://discourse.vtk.org/t/vtkpolydataconnectivityfilter-reverse/4744)

<div class="topic-metadata">

**Author:** [@EmileSonneveld](https://discourse.vtk.org/u/EmileSonneveld)\
**Replies:** 1\
**Last updated:** [November 27, 2020, 2:26pm UTC](https://discourse.vtk.org/t/vtkpolydataconnectivityfilter-reverse/4744 "2020-11-27T14:26:28Z")

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Hi, I would like to select all clusters except for the one that is close to the SetClosestPoint. Is there away to get the clusters sorted on distance? I played with the following code, but did not find a good combinati…

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## [How are world coordinates represented in the shader of VTK?](https://discourse.vtk.org/t/how-are-world-coordinates-represented-in-the-shader-of-vtk/4740)

<div class="topic-metadata">

**Author:** [@Jone7](https://discourse.vtk.org/u/Jone7)\
**Replies:** 1\
**Last updated:** [November 27, 2020, 12:22pm UTC](https://discourse.vtk.org/t/how-are-world-coordinates-represented-in-the-shader-of-vtk/4740 "2020-11-27T12:22:50Z")

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Since I want to do some lighting calculations in the Shader, I need the world coordinates of the light source, camera, and vertex, but when I modify the Shader, it seems that I can only get the view coordinates.Is there …

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## [How to solve the Line plot error?](https://discourse.vtk.org/t/how-to-solve-the-line-plot-error/4691)

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**Author:** [@nia38](https://discourse.vtk.org/u/nia38)\
**Replies:** 7\
**Last updated:** [November 27, 2020, 11:40am UTC](https://discourse.vtk.org/t/how-to-solve-the-line-plot-error/4691 "2020-11-27T11:40:58Z")

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I’m referring to an example of a line plot, and if the button is pressed with MFC, it’s printed on picture control. It works normally when the button is pressed for the first time, but if you plot it again, an error wil…

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## [Python - Dynamically change the opacity values of vtkPieceWiseFunction()](https://discourse.vtk.org/t/python-dynamically-change-the-opacity-values-of-vtkpiecewisefunction/4698)

<div class="topic-metadata">

**Author:** [@Gibser](https://discourse.vtk.org/u/Gibser)\
**Replies:** 2\
**Last updated:** [November 26, 2020, 11:45am UTC](https://discourse.vtk.org/t/python-dynamically-change-the-opacity-values-of-vtkpiecewisefunction/4698 "2020-11-26T11:45:05Z")

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Hi everyone, this is my first post here. I used vtkplotter to show a 3d model starting from dicom scans with the following code: import vtk from vtkplotter import \* import numpy as np from vtkmodules.vtkCommonDataModel …

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## [SIGSEGV (Segmentation fault) on freeing memory vtkSmartPointer\<vtkImageData\> (NIFTY)](https://discourse.vtk.org/t/sigsegv-segmentation-fault-on-freeing-memory-vtksmartpointer-vtkimagedata-nifty/4736)

<div class="topic-metadata">

**Author:** [@IVarha](https://discourse.vtk.org/u/IVarha)\
**Replies:** 2\
**Last updated:** [November 26, 2020, 10:59am UTC](https://discourse.vtk.org/t/sigsegv-segmentation-fault-on-freeing-memory-vtksmartpointer-vtkimagedata-nifty/4736 "2020-11-26T10:59:44Z")

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Hello support comumity, I have Segmentation fault error when I am freeing memory. (I use nifty reader to get an image) Here how my parts of source code look like : class NiftiImage { private: vtkSmartPointer niimg …

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## [Linux VTK Build error: The version of Python is unknown](https://discourse.vtk.org/t/linux-vtk-build-error-the-version-of-python-is-unknown/3899)

<div class="topic-metadata">

**Author:** [@wsherman](https://discourse.vtk.org/u/wsherman)\
**Replies:** 1\
**Last updated:** [November 25, 2020, 10:42pm UTC](https://discourse.vtk.org/t/linux-vtk-build-error-the-version-of-python-is-unknown/3899 "2020-11-25T22:42:44Z")

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Hello, I’m attempting to do a VTK build using the source within the ParaView 5.8.1-RC1 source download. I’m encountering several errors, but I’ll stick with one per discussion thread. I’m building on “CentOS Linux r…

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## [How can I fix a build error?](https://discourse.vtk.org/t/how-can-i-fix-a-build-error/4690)

<div class="topic-metadata">

**Author:** [@nia38](https://discourse.vtk.org/u/nia38)\
**Replies:** 5\
**Last updated:** [November 25, 2020, 10:14pm UTC](https://discourse.vtk.org/t/how-can-i-fix-a-build-error/4690 "2020-11-25T22:14:08Z")

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VS2019 is in use, and you are trying to build VTK-9.0.1 with Cmake. The following error occurs when Cmake is run: How should I handle this?

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## [png images can't show to renderwindow](https://discourse.vtk.org/t/png-images-cant-show-to-renderwindow/4722)

<div class="topic-metadata">

**Author:** [@Lisa](https://discourse.vtk.org/u/Lisa)\
**Replies:** 1\
**Last updated:** [November 25, 2020, 10:04pm UTC](https://discourse.vtk.org/t/png-images-cant-show-to-renderwindow/4722 "2020-11-25T22:04:50Z")

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Based on vtk8.2.0,use vtkImageActor and vtkPNGReader to render png images,but png images can’t show to renderwindow On some machines.

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## [build errors on Raspberry Pi 64bit beta OS - for use with AppCSXCAD](https://discourse.vtk.org/t/build-errors-on-raspberry-pi-64bit-beta-os-for-use-with-appcsxcad/3724)

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**Author:** [@Simon\_M](https://discourse.vtk.org/u/Simon_M)\
**Replies:** 1\
**Last updated:** [November 25, 2020, 7:26pm UTC](https://discourse.vtk.org/t/build-errors-on-raspberry-pi-64bit-beta-os-for-use-with-appcsxcad/3724 "2020-11-25T19:26:30Z")

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Hello everyone, please go easy on me - I’m pretty new to building anything on Linux (mainly low level embedded stuff) and I don’t know what information is required to make a question post that people can engage with. I’l…

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## [Building OpenCascade 7.5.0 with VTK 9.0.1](https://discourse.vtk.org/t/building-opencascade-7-5-0-with-vtk-9-0-1/4673)

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**Author:** [@Richard\_Shaw](https://discourse.vtk.org/u/Richard_Shaw)\
**Replies:** 22\
**Last updated:** [November 25, 2020, 4:19pm UTC](https://discourse.vtk.org/t/building-opencascade-7-5-0-with-vtk-9-0-1/4673 "2020-11-25T16:19:01Z")

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OCC 7.4 did not support vtk 9.x at all, but we made a bit of progress trying to build with 7.5.0 until here: \[ 90%\] Building CXX object src/TKIVtkDraw/CMakeFiles/TKIVtkDraw.dir/\_\_/IVtkDraw/IVtkDraw.cxx.o cd /builddir/bu…

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## [Get Interpolated image value for (x,y,z) point coordinate (BSpline)](https://discourse.vtk.org/t/get-interpolated-image-value-for-x-y-z-point-coordinate-bspline/4726)

<div class="topic-metadata">

**Author:** [@IVarha](https://discourse.vtk.org/u/IVarha)\
**Replies:** 3\
**Last updated:** [November 25, 2020, 3:35pm UTC](https://discourse.vtk.org/t/get-interpolated-image-value-for-x-y-z-point-coordinate-bspline/4726 "2020-11-25T15:35:54Z")

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Hello vtk Support community, I am using vtk for processing of 3d Nifti images and want to get interpolated value from (x,y,z)- I entered them in voxel coordinate space. W this-\>bspline\_coeff = vtkSmartPointer::New(); …

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## [How to draw rectangle where the specific position?](https://discourse.vtk.org/t/how-to-draw-rectangle-where-the-specific-position/4729)

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**Author:** [@nia38](https://discourse.vtk.org/u/nia38)\
**Replies:** 0\
**Last updated:** [November 25, 2020, 2:31am UTC](https://discourse.vtk.org/t/how-to-draw-rectangle-where-the-specific-position/4729 "2020-11-25T02:31:18Z")

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Hello, I used VS2019 and vtk-8.9 version. My plan is that: When the slide Bar(by using mfc component) is changing, drawing the rectangle on image viewer with slide bar’s value(the y-axis value). So, I referred the Bo…

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## [read data array with integral types from file?](https://discourse.vtk.org/t/read-data-array-with-integral-types-from-file/4680)

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**Author:** [@wenyan4work](https://discourse.vtk.org/u/wenyan4work)\
**Replies:** 4\
**Last updated:** [November 24, 2020, 6:45pm UTC](https://discourse.vtk.org/t/read-data-array-with-integral-types-from-file/4680 "2020-11-24T18:45:23Z")

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I’m trying to write a simple file reader to load the int32 and int64 data fields from a polydata file, with name ‘gid’. The VTK document (https://vtk.org/Wiki/VTK/Tutorials/DataArrays#vtkDataArray) says the old API conve…

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## [2D Surface cutter development](https://discourse.vtk.org/t/2d-surface-cutter-development/4481)

<div class="topic-metadata">

**Author:** [@jaswantp](https://discourse.vtk.org/u/jaswantp)\
**Replies:** 12\
**Last updated:** [November 24, 2020, 2:46pm UTC](https://discourse.vtk.org/t/2d-surface-cutter-development/4481 "2020-11-24T14:46:14Z")

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It appears the vtkCookieCutter doesn’t yet have an InsideOut option. vtkClipDataSet is not exactly precise for 2D surfaces. This MR has certain issues. After tinkering with vtkCookieCutter, I felt it needed to be redesi…

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## [Bug in vtkMultiBlockPLOT3DReader](https://discourse.vtk.org/t/bug-in-vtkmultiblockplot3dreader/4650)

<div class="topic-metadata">

**Author:** [@celynchgt](https://discourse.vtk.org/u/celynchgt)\
**Replies:** 3\
**Last updated:** [November 24, 2020, 1:36am UTC](https://discourse.vtk.org/t/bug-in-vtkmultiblockplot3dreader/4650 "2020-11-24T01:36:05Z")

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There appears to be a bug in vtkMultiBlockPLOT3DReader, specifically in the way it guesses the format of the file. I’m using whatever version of VTK is distributed with ParaView 5.8.1. First, I try to read the file wit…

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## [UWP (C++) Render Window Wrapper](https://discourse.vtk.org/t/uwp-c-render-window-wrapper/3995)

<div class="topic-metadata">

**Author:** [@Ugur](https://discourse.vtk.org/u/Ugur)\
**Replies:** 5\
**Last updated:** [November 19, 2020, 3:11pm UTC](https://discourse.vtk.org/t/uwp-c-render-window-wrapper/3995 "2020-11-19T15:11:58Z")

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Hi everybody, I am new to VTK and currently working with Qt and QVTKOpenGLNativeWidget. Everything works as expected. My question is that, is there also a wrapper for UWP (C++) platform? Kind regards Ugur

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## [some question](https://discourse.vtk.org/t/some-question/4717)

<div class="topic-metadata">

**Author:** [@cuger\_k](https://discourse.vtk.org/u/cuger_k)\
**Replies:** 0\
**Last updated:** [November 23, 2020, 12:54pm UTC](https://discourse.vtk.org/t/some-question/4717 "2020-11-23T12:54:03Z")

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When I run the provided examples such as DelimitedTextReader，I found that Skipping DelimitedTextReader in the cmake. How can I solve it

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## [Regarding how to modify image point/cell data](https://discourse.vtk.org/t/regarding-how-to-modify-image-point-cell-data/4714)

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**Author:** [@semimodeling](https://discourse.vtk.org/u/semimodeling)\
**Replies:** 0\
**Last updated:** [November 23, 2020, 7:25am UTC](https://discourse.vtk.org/t/regarding-how-to-modify-image-point-cell-data/4714 "2020-11-23T07:25:33Z")

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Dear all, I am new to VTK and I want to ask a question regarding how to modify point and cell data. I am not very familiar with all the concepts yet, so please forgive me if I made any mistakes regarding the naming of o…

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## [How bind texture to a sampler?](https://discourse.vtk.org/t/how-bind-texture-to-a-sampler/4709)

<div class="topic-metadata">

**Author:** [@Jone7](https://discourse.vtk.org/u/Jone7)\
**Replies:** 2\
**Last updated:** [November 23, 2020, 2:32am UTC](https://discourse.vtk.org/t/how-bind-texture-to-a-sampler/4709 "2020-11-23T02:32:46Z")

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I use AddFragmentShaderReplacement for fragment shader added “uniform sampler2D s”, Can someone tell me how to bind a texture to “sampler2D s” in VTK?

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## [How to find convex hull of a set of 3D points？](https://discourse.vtk.org/t/how-to-find-convex-hull-of-a-set-of-3d-points/4591)

<div class="topic-metadata">

**Author:** [@WangZP10969](https://discourse.vtk.org/u/WangZP10969)\
**Replies:** 5\
**Last updated:** [November 22, 2020, 1:14pm UTC](https://discourse.vtk.org/t/how-to-find-convex-hull-of-a-set-of-3d-points/4591 "2020-11-22T13:14:48Z")

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How to find the convex hull of a set of 3D points? I did not find a method in the VTK class. Similar functions are vtkHull and vtkPointsProjectedHull, but from the description it is not a way to obtain a set of 3D point …

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## [how to you pass the STL as a parameter in PyTHON using the Argarse module](https://discourse.vtk.org/t/how-to-you-pass-the-stl-as-a-parameter-in-python-using-the-argarse-module/4710)

<div class="topic-metadata">

**Author:** [@wanglongday](https://discourse.vtk.org/u/wanglongday)\
**Replies:** 0\
**Last updated:** [November 21, 2020, 10:10am UTC](https://discourse.vtk.org/t/how-to-you-pass-the-stl-as-a-parameter-in-python-using-the-argarse-module/4710 "2020-11-21T10:10:42Z")

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how to you pass the STL as a parameter in PyTHON using the Argarse module

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## [How use a 2D array in VTK to produce a 2D texture](https://discourse.vtk.org/t/how-use-a-2d-array-in-vtk-to-produce-a-2d-texture/4701)

<div class="topic-metadata">

**Author:** [@Jone7](https://discourse.vtk.org/u/Jone7)\
**Replies:** 1\
**Last updated:** [November 21, 2020, 1:28am UTC](https://discourse.vtk.org/t/how-use-a-2d-array-in-vtk-to-produce-a-2d-texture/4701 "2020-11-21T01:28:18Z")

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I want to convert an array into a 2D texture and pass it into shader’s uniform sampler2D variable. Is there any good way?

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