# A strange slice during MPR

**URL:** <https://discourse.vtk.org/t/a-strange-slice-during-mpr/11099>\
**Category:** Development\
**Tags:** code\
**Created:** [March 31, 2023, 6:15am UTC](https://discourse.vtk.org/t/a-strange-slice-during-mpr/11099 "2023-03-31T06:15:54Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![marlon.ma](https://discourse.vtk.org/user_avatar/discourse.vtk.org/marlon.ma/32/6091_2.png) [@marlon.ma](https://discourse.vtk.org/u/marlon.ma)\
**Post date:** [March 31, 2023, 6:15am UTC](https://discourse.vtk.org/t/a-strange-slice-during-mpr/11099/1 "2023-03-31T06:15:54Z")

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![image](https://discourse.vtk.org/uploads/default/original/2X/e/ee43b95542e2e0e84b6f11f01637473b7ecd9b9c.png)  
My goal is to have two sets of mpr images. The driven mpr completely follows the active mpr. I synchronize vtkResliceCursor to complete the synchronization, but some unexpected images may appear at certain locations. What may be the reason for this？

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<div class="post-metadata">

**Author:** ![marlon.ma](https://discourse.vtk.org/user_avatar/discourse.vtk.org/marlon.ma/32/6091_2.png) [@marlon.ma](https://discourse.vtk.org/u/marlon.ma)\
**Post date:** [April 1, 2023, 2:38pm UTC](https://discourse.vtk.org/t/a-strange-slice-during-mpr/11099/2 "2023-04-01T14:38:30Z")

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( 46.624s) [主线程]vtkStreamingDemandDrive:874 ERR| vtkCompositeDataPipeline (000001CB66139940): The update extent specified in the information for output port 0 on algorithm vtkImageMapToColors (000001CB6613A480) is 0 255 0 511 0 0, which is outside the whole extent 0 511 0 255 0 0.  
( 46.627s) [] vtkImageData.cxx:2313 ERR| vtkImageData (000001CB672DEEE0): GetPointer: Pixel (0, 256, 0) not in current extent: (0, 511, 0, 255, 0, 0)  
( 46.628s) [] vtkImageData.cxx:2313 ERR| vtkImageData (000001CB672DEEE0): GetPointer: Pixel (0, 320, 0) not in current extent: (0, 511, 0, 255, 0, 0)  
( 46.628s) [] vtkImageData.cxx:2313 ERR| vtkImageData (000001CB672DEEE0): GetPointer: Pixel (0, 448, 0) not in current extent: (0, 511, 0, 255, 0, 0)  
( 46.628s) [] vtkImageData.cxx:2313 ERR| vtkImageData (000001CB672DEEE0): GetPointer: Pixel (0, 384, 0) not in current extent: (0, 511, 0, 255, 0, 0)