# Development

**URL:** https://discourse.vtk.org/c/development/7.md?page=38

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

**Page:** 39

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## [Polyline section colors](https://discourse.vtk.org/t/polyline-section-colors/5314)

<div class="topic-metadata">

**Author:** [@Guillaume\_Gillet](https://discourse.vtk.org/u/Guillaume_Gillet)\
**Replies:** 4\
**Last updated:** [March 4, 2021, 9:00am UTC](https://discourse.vtk.org/t/polyline-section-colors/5314 "2021-03-04T09:00:10Z")

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Hello, so i’m a new trainee and for my company i’m studying vtk in order to replace their 3D component, and for that reason i need to display boreholes as polylines, but the fact is that they want me to color each sectio…

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## [Export vtkDataSetMapper to glTF](https://discourse.vtk.org/t/export-vtkdatasetmapper-to-gltf/5292)

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**Author:** [@mostapha](https://discourse.vtk.org/u/mostapha)\
**Replies:** 4\
**Last updated:** [March 2, 2021, 7:16pm UTC](https://discourse.vtk.org/t/export-vtkdatasetmapper-to-gltf/5292 "2021-03-02T19:16:16Z")

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Hello everyone! This is my first post here and I hope that I have picked the right category! I’m trying to export an UnstructuredGrid to a glTF file using vtkGLTFExporter and it only generates empty files. I doubted that…

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## [VtkCellLocator and Java](https://discourse.vtk.org/t/vtkcelllocator-and-java/919)

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**Author:** [@Gilthalas](https://discourse.vtk.org/u/Gilthalas)\
**Replies:** 17\
**Last updated:** [March 2, 2021, 2:47pm UTC](https://discourse.vtk.org/t/vtkcelllocator-and-java/919 "2021-03-02T14:47:34Z")

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I’ve noticed that several of the methods in vtkCellLocator (as well as some other classes) don’t come over to Java. Are there any plans to improve this in the future?

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## [Difference between vtkContourFilter, vtkMarchingSquares and vtkMarchingContourFilter](https://discourse.vtk.org/t/difference-between-vtkcontourfilter-vtkmarchingsquares-and-vtkmarchingcontourfilter/5273)

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**Author:** [@Nina](https://discourse.vtk.org/u/Nina)\
**Replies:** 1\
**Last updated:** [February 28, 2021, 1:11pm UTC](https://discourse.vtk.org/t/difference-between-vtkcontourfilter-vtkmarchingsquares-and-vtkmarchingcontourfilter/5273 "2021-02-28T13:11:33Z")

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Hi; What is the difference between the three filters: vtkContourFilter, vtkMarchingSquares and vtkMarchingContourFilter. In the documentation, the definition is very similar but what is the difference in terms of precis…

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## [suggested improvement for pyramidal elements](https://discourse.vtk.org/t/suggested-improvement-for-pyramidal-elements/5263)

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**Author:** [@LucasGasparinoBSC](https://discourse.vtk.org/u/LucasGasparinoBSC)\
**Replies:** 7\
**Last updated:** [February 26, 2021, 3:51pm UTC](https://discourse.vtk.org/t/suggested-improvement-for-pyramidal-elements/5263 "2021-02-26T15:51:24Z")

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Greetings, I’ve started the task of implementing the Biquadratic pyramid in VTK (vtkBiQuadraticPyramid with 14 nodes), and noticed that both vtkQuadraticPyramid and vtkPyramid have issues when computing the Jacobian inv…

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## [What's the best thing to do (git vtk)](https://discourse.vtk.org/t/whats-the-best-thing-to-do-git-vtk/5261)

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**Author:** [@jaswantp](https://discourse.vtk.org/u/jaswantp)\
**Replies:** 4\
**Last updated:** [February 26, 2021, 3:39pm UTC](https://discourse.vtk.org/t/whats-the-best-thing-to-do-git-vtk/5261 "2021-02-26T15:39:47Z")

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@mwestphal As can be seen from this MR, my branch is quite old and lags behind master by 251 commits. I am a first-time contributor and would like to get advice on the best thing to do here. Should I carry on with new…

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## [About performance of method vtkImageViewer2.SetSlice(int)](https://discourse.vtk.org/t/about-performance-of-method-vtkimageviewer2-setslice-int/4803)

<div class="topic-metadata">

**Author:** [@learn\_forever](https://discourse.vtk.org/u/learn_forever)\
**Replies:** 20\
**Last updated:** [February 22, 2021, 3:44pm UTC](https://discourse.vtk.org/t/about-performance-of-method-vtkimageviewer2-setslice-int/4803 "2021-02-22T15:44:43Z")

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Hi, I did some performance profilling for the method vtkImageViewer2.SetSlice(int), and found that method consumed large amounts of CPU usage, especailly when continually setting different slices. Is this a known issue…

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## [Cross Compiling VTK for Mobile Architectures](https://discourse.vtk.org/t/cross-compiling-vtk-for-mobile-architectures/5193)

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**Author:** [@timt](https://discourse.vtk.org/u/timt)\
**Replies:** 6\
**Last updated:** [February 15, 2021, 9:11pm UTC](https://discourse.vtk.org/t/cross-compiling-vtk-for-mobile-architectures/5193 "2021-02-15T21:11:08Z")

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I am interested in consolidating our current functionality for cross-compiling VTK for mobile architectures (iOS, tvOS, Android, etc.). This is likely to have a lot of overlap with the new Apple M1 (arm64) chip support. …

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## [How do I inflate a mesh in vtk?](https://discourse.vtk.org/t/how-do-i-inflate-a-mesh-in-vtk/5178)

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**Author:** [@ymmx2](https://discourse.vtk.org/u/ymmx2)\
**Replies:** 5\
**Last updated:** [February 12, 2021, 3:58pm UTC](https://discourse.vtk.org/t/how-do-i-inflate-a-mesh-in-vtk/5178 "2021-02-12T15:58:50Z")

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I displayed a mesh with vtk and I need to make the mesh looking more like it is inflated The mesh has a lot of curves and I’m not able to get the result I expect. Here’s what I tried so far: the original mesh look lik…

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## [Addition: stack vector](https://discourse.vtk.org/t/addition-stack-vector/5168)

<div class="topic-metadata">

**Author:** [@Thomas\_Caissard](https://discourse.vtk.org/u/Thomas_Caissard)\
**Replies:** 8\
**Last updated:** [February 11, 2021, 12:20pm UTC](https://discourse.vtk.org/t/addition-stack-vector/5168 "2021-02-11T12:20:30Z")

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There are some places in VTK that could be improved using an array-like data structure: it would lie on the stack if its size is less than a compile-time knows size (typically twice the cache line size) otherwise lie on …

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## [Removal of math.h from VTK headers](https://discourse.vtk.org/t/removal-of-math-h-from-vtk-headers/5163)

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**Author:** [@dgobbi](https://discourse.vtk.org/u/dgobbi)\
**Replies:** 5\
**Last updated:** [February 10, 2021, 7:43pm UTC](https://discourse.vtk.org/t/removal-of-math-h-from-vtk-headers/5163 "2021-02-10T19:43:50Z")

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In !7572, I remove #include \<math.h\> from vtkSetGet.h (which is included by all VTK class headers). The reason for the removal is modernization of the code, but of course it will cause some (easily fixed) compile errors …

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## [Support for pathlib](https://discourse.vtk.org/t/support-for-pathlib/5085)

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**Author:** [@fepegar](https://discourse.vtk.org/u/fepegar)\
**Replies:** 13\
**Last updated:** [February 9, 2021, 6:31pm UTC](https://discourse.vtk.org/t/support-for-pathlib/5085 "2021-02-09T18:31:08Z")

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Hi all, Are there any plans to add pathlib support for the Python wrappers? (I’ve been recommended to ping @dgobbi about this)

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## [Why does vtkCamera auto adjust camera position after something rendered.](https://discourse.vtk.org/t/why-does-vtkcamera-auto-adjust-camera-position-after-something-rendered/3678)

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**Author:** [@veltia](https://discourse.vtk.org/u/veltia)\
**Replies:** 0\
**Last updated:** [July 1, 2020, 7:54am UTC](https://discourse.vtk.org/t/why-does-vtkcamera-auto-adjust-camera-position-after-something-rendered/3678 "2020-07-01T07:54:27Z")

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Hi all, I tried to set vtkCamera to make the origin of world coordinate to be the middle of the render window. It works if theres only a AxesActor display at the orgin. (actorAxes-\>SetPosition(0, 0, 0); But when I t…

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## [About API breaking changes](https://discourse.vtk.org/t/about-api-breaking-changes/1339)

<div class="topic-metadata">

**Author:** [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Replies:** 24\
**Last updated:** [February 4, 2021, 9:08am UTC](https://discourse.vtk.org/t/about-api-breaking-changes/1339 "2021-02-04T09:08:50Z")

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On a ParaView MR, we started having a discussion which should be discussed here. https://gitlab.kitware.com/paraview/paraview/merge\_requests/3396 ParaView uses VTK as a submodule and usually the developer that update t…

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## [Rendering a polyline on the top of other lines](https://discourse.vtk.org/t/rendering-a-polyline-on-the-top-of-other-lines/5069)

<div class="topic-metadata">

**Author:** [@Faizan](https://discourse.vtk.org/u/Faizan)\
**Replies:** 2\
**Last updated:** [February 3, 2021, 6:03pm UTC](https://discourse.vtk.org/t/rendering-a-polyline-on-the-top-of-other-lines/5069 "2021-02-03T18:03:28Z")

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Hello developers, Hello developers, I am stuck in a problem that seems a bit basic but still could not solve it yet. I am using multiple rendering layers to render different kinds of Fiber tracts (Red and orange) over…

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## [Cutter Output curve to mesh](https://discourse.vtk.org/t/cutter-output-curve-to-mesh/5116)

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**Author:** [@Anish\_Basnet](https://discourse.vtk.org/u/Anish_Basnet)\
**Replies:** 4\
**Last updated:** [February 2, 2021, 4:22pm UTC](https://discourse.vtk.org/t/cutter-output-curve-to-mesh/5116 "2021-02-02T16:22:43Z")

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Hello everyone, Is it possible to convert the output curve of a vtkCutter class to a mesh? I wanted to compute curvatures but vtkCurvatures only takes a polydata mesh as input. I tried using vtkDelaunay2D but the mesh i…

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## [Array resizing](https://discourse.vtk.org/t/array-resizing/5115)

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**Author:** [@olesenm](https://discourse.vtk.org/u/olesenm)\
**Replies:** 0\
**Last updated:** [February 1, 2021, 4:54pm UTC](https://discourse.vtk.org/t/array-resizing/5115 "2021-02-01T16:54:10Z")

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I was sifting through the openfoam reader and stumbled across something that looks to me like legacy code: // this is necessary due to the strange vtkDataArrayTemplate::Resize() // implementation when the array size is …

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## [Debug looking for DLLs with -gd suffix](https://discourse.vtk.org/t/debug-looking-for-dlls-with-gd-suffix/3300)

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**Author:** [@khlitoshi](https://discourse.vtk.org/u/khlitoshi)\
**Replies:** 2\
**Last updated:** [February 1, 2021, 11:06am UTC](https://discourse.vtk.org/t/debug-looking-for-dlls-with-gd-suffix/3300 "2021-02-01T11:06:34Z")

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I developed an application based on VTK 8.2. I compiled vtk from source in Debug and Release mode. When I run my application in debug mode it complains about not finding VTK Dll vtkChartsCore-8.2-gd.dll I compiled VTK …

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## [vtkStaticCellLocator throws error on IntersectWithLine](https://discourse.vtk.org/t/vtkstaticcelllocator-throws-error-on-intersectwithline/5095)

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**Author:** [@DFlyer](https://discourse.vtk.org/u/DFlyer)\
**Replies:** 1\
**Last updated:** [January 29, 2021, 7:37pm UTC](https://discourse.vtk.org/t/vtkstaticcelllocator-throws-error-on-intersectwithline/5095 "2021-01-29T19:37:16Z")

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I am trying to intersect a polydata ( tri mesh) with a line, I am using vtkStaticCellLocator filter as follows vtkSmartPointer\< vtkStaticCellLocator\> pCellLocator = vtkSmartPointer\<vtkStaticCellLocator\>::New(); pCellLoc…

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## [how can I show molecular orbital with vtk](https://discourse.vtk.org/t/how-can-i-show-molecular-orbital-with-vtk/5093)

<div class="topic-metadata">

**Author:** [@mjavan](https://discourse.vtk.org/u/mjavan)\
**Replies:** 1\
**Last updated:** [January 29, 2021, 3:32pm UTC](https://discourse.vtk.org/t/how-can-i-show-molecular-orbital-with-vtk/5093 "2021-01-29T15:32:46Z")

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I want read a gaussian cube file with vtkGaussianCubeReader and show isosurface of the Molecular orbitals similar as I found some class such as vtkProgrammableElectronicData and vtkMolecule but I dont know how can I se…

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## [vtkImageTracerWidget not receiving events on Mac (pyQt5). bug?](https://discourse.vtk.org/t/vtkimagetracerwidget-not-receiving-events-on-mac-pyqt5-bug/5052)

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**Author:** [@soren](https://discourse.vtk.org/u/soren)\
**Replies:** 5\
**Last updated:** [January 27, 2021, 9:45am UTC](https://discourse.vtk.org/t/vtkimagetracerwidget-not-receiving-events-on-mac-pyqt5-bug/5052 "2021-01-27T09:45:31Z")

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Hi, I posted this in support last week but with no luck. I am re-posting here as this is a potential bug based on differing results on Linux/Mac and with and without PyQt rendering. I have trouble with vtkImageTracerWi…

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## [Unhandled Rejection (TypeError): Cannot read property 'pixelRepresentation' of undefined](https://discourse.vtk.org/t/unhandled-rejection-typeerror-cannot-read-property-pixelrepresentation-of-undefined/5055)

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**Author:** [@MarkoNikovic](https://discourse.vtk.org/u/MarkoNikovic)\
**Replies:** 0\
**Last updated:** [January 25, 2021, 7:28pm UTC](https://discourse.vtk.org/t/unhandled-rejection-typeerror-cannot-read-property-pixelrepresentation-of-undefined/5055 "2021-01-25T19:28:01Z")

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Hello Everyone, How are you? I am using react-vtkjs-viewport module in our project (React Rescripts) I set initialize setting vtkRules in rescript.js for VTK. Now I have node mudule representation error I wish any…

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## [QT Signals and slots](https://discourse.vtk.org/t/qt-signals-and-slots/5053)

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**Author:** [@dporter](https://discourse.vtk.org/u/dporter)\
**Replies:** 1\
**Last updated:** [January 25, 2021, 6:06pm UTC](https://discourse.vtk.org/t/qt-signals-and-slots/5053 "2021-01-25T18:06:42Z")

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I’ve spent a couple of days trying to get a my QPushButton to fire and signal and recognizing a slot. The strange thing is I’ve gotten gotten other button to work perfectly, and I set up this button the same exact way as…

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## [vtkErrorMacro with loguru now caught](https://discourse.vtk.org/t/vtkerrormacro-with-loguru-now-caught/4968)

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**Author:** [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)\
**Replies:** 18\
**Last updated:** [January 18, 2021, 6:21pm UTC](https://discourse.vtk.org/t/vtkerrormacro-with-loguru-now-caught/4968 "2021-01-18T18:21:52Z")

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A year or two ago, an effort was made to make sure that vtkErrorMacro codepaths would cause a test to fail. Bill Lorensen wrote the vtkTestErrorObserver class which may be used to capture errors from a specific vtkObject …

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## [make a vtkPolyData from Points and Cells](https://discourse.vtk.org/t/make-a-vtkpolydata-from-points-and-cells/5020)

<div class="topic-metadata">

**Author:** [@SArbabi](https://discourse.vtk.org/u/SArbabi)\
**Replies:** 7\
**Last updated:** [January 18, 2021, 1:32pm UTC](https://discourse.vtk.org/t/make-a-vtkpolydata-from-points-and-cells/5020 "2021-01-18T13:32:20Z")

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having a surface as a vtkPolyData like the one bellow, would it be possible to extract points and cells, and then again assemble them to a vtkPolyData like the surface we had first? vtkPolyData (0000022DAA05F6D0) Debu…

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## [get the output data of a vtk filter](https://discourse.vtk.org/t/get-the-output-data-of-a-vtk-filter/5017)

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**Author:** [@Christopher\_Wastell](https://discourse.vtk.org/u/Christopher_Wastell)\
**Replies:** 1\
**Last updated:** [January 15, 2021, 3:27pm UTC](https://discourse.vtk.org/t/get-the-output-data-of-a-vtk-filter/5017 "2021-01-15T15:27:56Z")

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Hi, I’m using a vtk filter to work on some input data. I see that the vtk filter has a method called GetOutputPort that pipes to the inputPort of the next block, but if I want to get the output of this filter and not pa…

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## [Seek help! What is the replacement of the inputport and outputport classes in vtk7.1.1?](https://discourse.vtk.org/t/seek-help-what-is-the-replacement-of-the-inputport-and-outputport-classes-in-vtk7-1-1/4993)

<div class="topic-metadata">

**Author:** [@Vettle](https://discourse.vtk.org/u/Vettle)\
**Replies:** 3\
**Last updated:** [January 15, 2021, 12:18am UTC](https://discourse.vtk.org/t/seek-help-what-is-the-replacement-of-the-inputport-and-outputport-classes-in-vtk7-1-1/4993 "2021-01-15T00:18:36Z")

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## [How to update texture of an already rendered actor in vtk python](https://discourse.vtk.org/t/how-to-update-texture-of-an-already-rendered-actor-in-vtk-python/5011)

<div class="topic-metadata">

**Author:** [@Debayan\_Ganguly](https://discourse.vtk.org/u/Debayan_Ganguly)\
**Replies:** 0\
**Last updated:** [January 14, 2021, 9:53pm UTC](https://discourse.vtk.org/t/how-to-update-texture-of-an-already-rendered-actor-in-vtk-python/5011 "2021-01-14T21:53:31Z")

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grid = rgb\_to\_vtk(np.ascontiguousarray(rgb)) texture = vtk.vtkTexture() texture.SetInputDataObject(grid) if interp: texture.InterpolateOn() actor\_obj.SetTexture(texture) I did this converted rgb image to vtk image…

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## [How to create a scalar bar with Matplolib colormaps?](https://discourse.vtk.org/t/how-to-create-a-scalar-bar-with-matplolib-colormaps/5002)

<div class="topic-metadata">

**Author:** [@MM8050](https://discourse.vtk.org/u/MM8050)\
**Replies:** 0\
**Last updated:** [January 14, 2021, 12:33pm UTC](https://discourse.vtk.org/t/how-to-create-a-scalar-bar-with-matplolib-colormaps/5002 "2021-01-14T12:33:45Z")

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Hello everyone, I am trying to implement a scalar bar for improving data reading. The particularity is that I want to have a specific colormap for the data and the scalar bar. I am wondering whether or not it is possibl…

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## [VTK9 regression: vtkFollower unpickable](https://discourse.vtk.org/t/vtk9-regression-vtkfollower-unpickable/4991)

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**Author:** [@marcomusy](https://discourse.vtk.org/u/marcomusy)\
**Replies:** 2\
**Last updated:** [January 13, 2021, 2:33am UTC](https://discourse.vtk.org/t/vtk9-regression-vtkfollower-unpickable/4991 "2021-01-13T02:33:05Z")

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This works fine in vtk8 but fails in vtk9 for objects with opacity \< 1: import vtk cone = vtk.vtkConeSource() coneMapper = vtk.vtkPolyDataMapper() coneMapper.SetInputConnection(cone.GetOutputPort()) coneActor = vtk.v…

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