# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=143

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

**Page:** 144

---

## [How Can I Pick from an Image that is Not the Top Layer in a vtkImageStack?](https://discourse.vtk.org/t/how-can-i-pick-from-an-image-that-is-not-the-top-layer-in-a-vtkimagestack/2278)

<div class="topic-metadata">

**Author:** [@MichelleKline](https://discourse.vtk.org/u/MichelleKline)\
**Replies:** 2\
**Last updated:** [December 16, 2019, 5:50pm UTC](https://discourse.vtk.org/t/how-can-i-pick-from-an-image-that-is-not-the-top-layer-in-a-vtkimagestack/2278 "2019-12-16T17:50:38Z")

</div>

Hello, In my application, I am rendering two images overlayed on one another. The images are vtkImageSlice(s) and I use a vtkImageStack to store both images. The topmost image is cropped in such a way that it’s exent …

---

## [How to compile VTK 8.2.0 with gcc-7 and Qt 5.9.1 on MacOS 10.14?](https://discourse.vtk.org/t/how-to-compile-vtk-8-2-0-with-gcc-7-and-qt-5-9-1-on-macos-10-14/2194)

<div class="topic-metadata">

**Author:** [@benjaminwelle](https://discourse.vtk.org/u/benjaminwelle)\
**Replies:** 15\
**Last updated:** [December 16, 2019, 1:06pm UTC](https://discourse.vtk.org/t/how-to-compile-vtk-8-2-0-with-gcc-7-and-qt-5-9-1-on-macos-10-14/2194 "2019-12-16T13:06:19Z")

</div>

I am trying hard since a while already to compile VTK 8.2.0 with CMake 3.16.0, Qt 5.9.1 and MacPorts gcc7 7.4.0\_3 on MacOS Mojave, i.e. with MacOSX10.14.sdk (Xcode), but I can’t get it to work. I had the same problems al…

---

## [How can I pick a modified polydata?(complete code supplied)](https://discourse.vtk.org/t/how-can-i-pick-a-modified-polydata-complete-code-supplied/2269)

<div class="topic-metadata">

**Author:** [@tdchen](https://discourse.vtk.org/u/tdchen)\
**Replies:** 1\
**Last updated:** [December 16, 2019, 1:45am UTC](https://discourse.vtk.org/t/how-can-i-pick-a-modified-polydata-complete-code-supplied/2269 "2019-12-16T01:45:41Z")

</div>

The following program display a triangle firstly. When you hit the triangle, it splits into 2 triangles. The problem is: after splitting, you can’t hit the large triangle. What is the reason? Hope your reply. #inclu…

---

## [How can I achieve transparent out-of-range colors with the vtk color transfer function?](https://discourse.vtk.org/t/how-can-i-achieve-transparent-out-of-range-colors-with-the-vtk-color-transfer-function/2257)

<div class="topic-metadata">

**Author:** [@MichelleKline](https://discourse.vtk.org/u/MichelleKline)\
**Replies:** 6\
**Last updated:** [December 13, 2019, 10:27pm UTC](https://discourse.vtk.org/t/how-can-i-achieve-transparent-out-of-range-colors-with-the-vtk-color-transfer-function/2257 "2019-12-13T22:27:17Z")

</div>

Hello, I am attempting to use the vtkColorTransferFunction or the vtkDiscretizableColorTransferFunction class to create a custom colormap for my vtk-based application. I am using this class in lieu of the vtkLookupTabl…

---

## [can vtk use mutltiple GPU together](https://discourse.vtk.org/t/can-vtk-use-mutltiple-gpu-together/2275)

<div class="topic-metadata">

**Author:** [@baoyun](https://discourse.vtk.org/u/baoyun)\
**Replies:** 0\
**Last updated:** [December 13, 2019, 7:31pm UTC](https://discourse.vtk.org/t/can-vtk-use-mutltiple-gpu-together/2275 "2019-12-13T19:31:49Z")

</div>

If I want to use all my GPU to display many volumes at same time, try to utilize all available GPU memory. Can I do this using VTK? Thanks

---

## [Move sphere along polyline](https://discourse.vtk.org/t/move-sphere-along-polyline/2225)

<div class="topic-metadata">

**Author:** [@Romain](https://discourse.vtk.org/u/Romain)\
**Replies:** 3\
**Last updated:** [December 13, 2019, 2:36pm UTC](https://discourse.vtk.org/t/move-sphere-along-polyline/2225 "2019-12-13T14:36:49Z")

</div>

Hi everyone, I try to move a sphere along a Polyline. I use vtkPropPicker to get the current mouse position then I use vtkCellLocator to found the closest point from the picked position to the Polyline using FindCloses…

---

## [Real time viewing of geometry data from a source file](https://discourse.vtk.org/t/real-time-viewing-of-geometry-data-from-a-source-file/2272)

<div class="topic-metadata">

**Author:** [@jk7070](https://discourse.vtk.org/u/jk7070)\
**Replies:** 0\
**Last updated:** [December 13, 2019, 2:04pm UTC](https://discourse.vtk.org/t/real-time-viewing-of-geometry-data-from-a-source-file/2272 "2019-12-13T14:04:15Z")

</div>

Hi, I have what I think is a simple question. I have a simple shape, call it a Quad. The points of the Quad are initially read from a file, in this case an excel workbook. What I want is to be able to update the points i…

---

## [Scaling to 0.001 produces unexpected result](https://discourse.vtk.org/t/scaling-to-0-001-produces-unexpected-result/2248)

<div class="topic-metadata">

**Author:** [@idhamari](https://discourse.vtk.org/u/idhamari)\
**Replies:** 2\
**Last updated:** [December 13, 2019, 11:40am UTC](https://discourse.vtk.org/t/scaling-to-0-001-produces-unexpected-result/2248 "2019-12-13T11:40:27Z")

</div>

Dear all I am trying to scale a mesh to 0.001 but I get a mesh that does not look like the original one. Here is the code I used: reader = vtk.vtkSTLReader() reader.SetFileName(inputFilename) reader.Update…

---

## [WindowToImageFilter reading old buffer images](https://discourse.vtk.org/t/windowtoimagefilter-reading-old-buffer-images/2267)

<div class="topic-metadata">

**Author:** [@sandress](https://discourse.vtk.org/u/sandress)\
**Replies:** 0\
**Last updated:** [December 13, 2019, 12:35am UTC](https://discourse.vtk.org/t/windowtoimagefilter-reading-old-buffer-images/2267 "2019-12-13T00:35:14Z")

</div>

I’m using VTK to create a series of DRR images using offscreen rendering and the vtkWindowToImageFilter. Therefore I’m randomly changing the Camera position and save this transform to the then generated DRR image. Howev…

---

## [Piece ID from vtkXMLPUnstructuredGridReader](https://discourse.vtk.org/t/piece-id-from-vtkxmlpunstructuredgridreader/2265)

<div class="topic-metadata">

**Author:** [@banesullivan](https://discourse.vtk.org/u/banesullivan)\
**Replies:** 1\
**Last updated:** [December 12, 2019, 11:32pm UTC](https://discourse.vtk.org/t/piece-id-from-vtkxmlpunstructuredgridreader/2265 "2019-12-12T23:32:48Z")

</div>

When using the parallel VTU file reader (vtkXMLPUnstructuredGridReader), is there a way to have the reader automatically add an array corresponding to the piece of the mesh? (e.g. integers from 0 to NumberOfPeices I hav…

---

## [10 bit per channel RGB](https://discourse.vtk.org/t/10-bit-per-channel-rgb/2262)

<div class="topic-metadata">

**Author:** [@iheartvtoolkit](https://discourse.vtk.org/u/iheartvtoolkit)\
**Replies:** 2\
**Last updated:** [December 12, 2019, 3:28pm UTC](https://discourse.vtk.org/t/10-bit-per-channel-rgb/2262 "2019-12-12T15:28:08Z")

</div>

Hi, I am wondering if there are any low/high-level options to change color-manipulating classes such as vtkLookupTable, vtkImageMapToColors, etc, to use 10 bpc instead of 8? Background: Trying to pass 10 bpc QC tests. I…

---

## [Reading csv and display it as 2D image](https://discourse.vtk.org/t/reading-csv-and-display-it-as-2d-image/2263)

<div class="topic-metadata">

**Author:** [@Lavanya](https://discourse.vtk.org/u/Lavanya)\
**Replies:** 0\
**Last updated:** [December 12, 2019, 10:30am UTC](https://discourse.vtk.org/t/reading-csv-and-display-it-as-2d-image/2263 "2019-12-12T10:30:47Z")

</div>

Hi everyone, I am trying to read a csv file and display it as image. I’m very new to C++ and Vtk. The csv file has following data: 1 2 3 4 10 20 30 40 50 60 70 80 Any suggestions please??

---

## [Synchronize windows level of vtkResliceImageViewer with multiple renderers](https://discourse.vtk.org/t/synchronize-windows-level-of-vtkresliceimageviewer-with-multiple-renderers/2260)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 0\
**Last updated:** [December 12, 2019, 9:57am UTC](https://discourse.vtk.org/t/synchronize-windows-level-of-vtkresliceimageviewer-with-multiple-renderers/2260 "2019-12-12T09:57:41Z")

</div>

Hi !! I have N slices in a layout shown in a single windows at the same time all slices. This layout is a vtkResliceImageViewer and each slice is a new renderer that is set up in a part of the viewport from the same vi…

---

## [Convert 2D ultrasound image to 3D](https://discourse.vtk.org/t/convert-2d-ultrasound-image-to-3d/1614)

<div class="topic-metadata">

**Author:** [@Qiangyun\_li](https://discourse.vtk.org/u/Qiangyun_li)\
**Replies:** 5\
**Last updated:** [December 12, 2019, 5:59am UTC](https://discourse.vtk.org/t/convert-2d-ultrasound-image-to-3d/1614 "2019-12-12T05:59:57Z")

</div>

I have 3D matrix and the pixel spacing about volume , how can l get volume render.

---

## [How to triangulate a surface from point cloud](https://discourse.vtk.org/t/how-to-triangulate-a-surface-from-point-cloud/2240)

<div class="topic-metadata">

**Author:** [@T4mmi](https://discourse.vtk.org/u/T4mmi)\
**Replies:** 5\
**Last updated:** [December 12, 2019, 5:39am UTC](https://discourse.vtk.org/t/how-to-triangulate-a-surface-from-point-cloud/2240 "2019-12-12T05:39:01Z")

</div>

Hi all, Quite new to vtk and meshing in general (got a raster processing background). I understand the concept of mesh (and polydata) as a tuple of : vertices/points (i.e. space coordinates): (x,y,z) in 3D cells (i.e…

---

## [How to get "connectivity", "offsets", "faces", "faceoffsets" array from "Cell" in unstructured polyhedral grid](https://discourse.vtk.org/t/how-to-get-connectivity-offsets-faces-faceoffsets-array-from-cell-in-unstructured-polyhedral-grid/2244)

<div class="topic-metadata">

**Author:** [@pcs](https://discourse.vtk.org/u/pcs)\
**Replies:** 2\
**Last updated:** [December 12, 2019, 5:27am UTC](https://discourse.vtk.org/t/how-to-get-connectivity-offsets-faces-faceoffsets-array-from-cell-in-unstructured-polyhedral-grid/2244 "2019-12-12T05:27:50Z")

</div>

I have an XML unstructured grid with polyhedral elements and would like to read it using Python for post-processing analysis of a simulation. I can read the file with vtkXMLUnstructuredGridReader and successfully read so…

---

## [Obtaining the CellData of a given Cell](https://discourse.vtk.org/t/obtaining-the-celldata-of-a-given-cell/2210)

<div class="topic-metadata">

**Author:** [@balborian](https://discourse.vtk.org/u/balborian)\
**Replies:** 1\
**Last updated:** [December 11, 2019, 11:01pm UTC](https://discourse.vtk.org/t/obtaining-the-celldata-of-a-given-cell/2210 "2019-12-11T23:01:39Z")

</div>

Consider the code below: reader = PVDReader(FileName="./function.pvd") data = servermanager.Fetch(reader) cells = data.GetCells() cells.InitTraversal() cell\_data\_arr = data.GetCellData().GetArray(0) for i in range(c…

---

## [Create a vtkTexture from in-memory imagedata](https://discourse.vtk.org/t/create-a-vtktexture-from-in-memory-imagedata/2227)

<div class="topic-metadata">

**Author:** [@Michael\_Jackson](https://discourse.vtk.org/u/Michael_Jackson)\
**Replies:** 9\
**Last updated:** [December 11, 2019, 2:03pm UTC](https://discourse.vtk.org/t/create-a-vtktexture-from-in-memory-imagedata/2227 "2019-12-11T14:03:43Z")

</div>

I am trying to create a vtkTexture for use on a Quad object. I have the data already existing in memory as an array of floating point values between about 0.3 and 0.93. I have created a vtkLookupTable to map from the val…

---

## [Z-Buffer Values Problem with Camera](https://discourse.vtk.org/t/z-buffer-values-problem-with-camera/2224)

<div class="topic-metadata">

**Author:** [@Alex1](https://discourse.vtk.org/u/Alex1)\
**Replies:** 3\
**Last updated:** [December 11, 2019, 12:26pm UTC](https://discourse.vtk.org/t/z-buffer-values-problem-with-camera/2224 "2019-12-11T12:26:45Z")

</div>

Hi all, I try to get the zBuffer Values from my vtkRenderWindow with renWin-\>GetZbufferData(x1,y1,x2,y2) and it works fine, if I print the Image to file I get this : But as soon as I add a Camera to my renderer it do…

---

## [AttributeError: 'module' object has no attribute 'vtkOBJWriter'](https://discourse.vtk.org/t/attributeerror-module-object-has-no-attribute-vtkobjwriter/2249)

<div class="topic-metadata">

**Author:** [@idhamari](https://discourse.vtk.org/u/idhamari)\
**Replies:** 2\
**Last updated:** [December 10, 2019, 5:05pm UTC](https://discourse.vtk.org/t/attributeerror-module-object-has-no-attribute-vtkobjwriter/2249 "2019-12-10T17:05:11Z")

</div>

Dear all, Why I get an error saying this module is missing? Python 2.7.15+ (default, Oct 7 2019, 17:39:04) \[GCC 7.4.0\] on linux2 Type "help", "copyright", "credits" or "license" for more information. \>\>\> import vtk \>\>…

---

## [Can't run some VTK examples in Qt](https://discourse.vtk.org/t/cant-run-some-vtk-examples-in-qt/2242)

<div class="topic-metadata">

**Author:** [@kerim](https://discourse.vtk.org/u/kerim)\
**Replies:** 7\
**Last updated:** [December 10, 2019, 4:02pm UTC](https://discourse.vtk.org/t/cant-run-some-vtk-examples-in-qt/2242 "2019-12-10T16:02:49Z")

</div>

Hi, I installed VTK-8.2.0 from source on Windows x64 with MSVC x64. I upload CMakeCache from CMake GUI. I can run this example CylinderExample but I can’t run this ParametricKuenDemo. If I try to run this example I ge…

---

## [attempt to render to unbound program](https://discourse.vtk.org/t/attempt-to-render-to-unbound-program/2216)

<div class="topic-metadata">

**Author:** [@aglv](https://discourse.vtk.org/u/aglv)\
**Replies:** 2\
**Last updated:** [December 10, 2019, 10:23am UTC](https://discourse.vtk.org/t/attempt-to-render-to-unbound-program/2216 "2019-12-10T10:23:06Z")

</div>

The software I’m working on uses multiple vtkCocoaGLView instances to display stuff. Since updating to recent VTK versions from VTK 5, the rendering pipeline stops working when switching between windows. I tracked this …

---

## [after rotate the reslicecursor, how to get the slice count?](https://discourse.vtk.org/t/after-rotate-the-reslicecursor-how-to-get-the-slice-count/1622)

<div class="topic-metadata">

**Author:** [@pingdan](https://discourse.vtk.org/u/pingdan)\
**Replies:** 10\
**Last updated:** [December 9, 2019, 6:44pm UTC](https://discourse.vtk.org/t/after-rotate-the-reslicecursor-how-to-get-the-slice-count/1622 "2019-12-09T18:44:19Z")

</div>

vtkImagePlaneWidget,vtkResliceCursorWidget,vtkResliceCursor,vtkResliceCursorThickLineRepresentation I use these classes to display MPR.when I rotate the reslicecursor with the mouse, we can the see the reslicecursor rot…

---

## [Switching between renderers in vtkRenderWindow](https://discourse.vtk.org/t/switching-between-renderers-in-vtkrenderwindow/2234)

<div class="topic-metadata">

**Author:** [@sboogert](https://discourse.vtk.org/u/sboogert)\
**Replies:** 1\
**Last updated:** [December 9, 2019, 6:40pm UTC](https://discourse.vtk.org/t/switching-between-renderers-in-vtkrenderwindow/2234 "2019-12-09T18:40:18Z")

</div>

So I have an application where I have multiple vtkRenderers which I would like to quickly switch between in my vtkRenderWindow. The vtkRenderWindow appears to keep a collection of renderers, are all of these supposed to …

---

## [VTK Scene Graph](https://discourse.vtk.org/t/vtk-scene-graph/2214)

<div class="topic-metadata">

**Author:** [@RJP](https://discourse.vtk.org/u/RJP)\
**Replies:** 5\
**Last updated:** [December 9, 2019, 3:26pm UTC](https://discourse.vtk.org/t/vtk-scene-graph/2214 "2019-12-09T15:26:14Z")

</div>

Hi all, After years of using VTK, there’s one thing that’s been bothering us and we don’t know how to solve it yet: We want to have a Scene Graph in VTK that can be shared across multiple renderwindows. We noticed tha…

---

## [2D Triangle intersection](https://discourse.vtk.org/t/2d-triangle-intersection/2230)

<div class="topic-metadata">

**Author:** [@marcomusy](https://discourse.vtk.org/u/marcomusy)\
**Replies:** 0\
**Last updated:** [December 8, 2019, 2:04am UTC](https://discourse.vtk.org/t/2d-triangle-intersection/2230 "2019-12-08T02:04:54Z")

</div>

I wonder if there is a way of finding the overlapping area of two arbitrary triangles in 2D. I could only come up with the idea of extruding the 2 triangles (vtkRotationalExtrusionFilter) and find the intersection with v…

---

## [Display the mesh of vtk.vtkSphereSource ()](https://discourse.vtk.org/t/display-the-mesh-of-vtk-vtkspheresource/2221)

<div class="topic-metadata">

**Author:** [@minmin](https://discourse.vtk.org/u/minmin)\
**Replies:** 1\
**Last updated:** [December 6, 2019, 7:24am UTC](https://discourse.vtk.org/t/display-the-mesh-of-vtk-vtkspheresource/2221 "2019-12-06T07:24:35Z")

</div>

I can display the surface, but how can I display it in wireframe? Thank you.

---

## [How to use VTK](https://discourse.vtk.org/t/how-to-use-vtk/2212)

<div class="topic-metadata">

**Author:** [@minmin](https://discourse.vtk.org/u/minmin)\
**Replies:** 0\
**Last updated:** [December 5, 2019, 8:03am UTC](https://discourse.vtk.org/t/how-to-use-vtk/2212 "2019-12-05T08:03:03Z")

</div>

Sorry for the amateur question. I want to use vtkSelectEnclosedPoints. Even if you look at https://vtk.org/doc/nightly/html/classvtkSelectEnclosedPoints.html, it is not easy to understand. Are there any examples of Sphe…

---

## [compute tangents and normal planes of a curve](https://discourse.vtk.org/t/compute-tangents-and-normal-planes-of-a-curve/902)

<div class="topic-metadata">

**Author:** [@cyanxwh](https://discourse.vtk.org/u/cyanxwh)\
**Replies:** 2\
**Last updated:** [December 5, 2019, 1:37am UTC](https://discourse.vtk.org/t/compute-tangents-and-normal-planes-of-a-curve/902 "2019-12-05T01:37:57Z")

</div>

Hi guys, I wonder how to compute the tangents and normal planes of a curve at a point on it using VTK. I have searched it on the Internet but cannot get a clear answer. Can anyone help me? Thanks.

---

## [How to do boolean operation on vtkPolyData?](https://discourse.vtk.org/t/how-to-do-boolean-operation-on-vtkpolydata/2208)

<div class="topic-metadata">

**Author:** [@tianaik](https://discourse.vtk.org/u/tianaik)\
**Replies:** 0\
**Last updated:** [December 5, 2019, 1:28am UTC](https://discourse.vtk.org/t/how-to-do-boolean-operation-on-vtkpolydata/2208 "2019-12-05T01:28:44Z")

</div>

Hi all, I would like to select a part of polydata with vtkInteractorStyleRubberBandPick, and I have realized it with vtkSelection and vtkSelectionNode. Here is the picture And I would like to select another part of p…

[Previous page](https://discourse.vtk.org/c/support/6.md?page=142)

[Next page](https://discourse.vtk.org/c/support/6.md?page=144)