# A Multi Volume Problem of VTK9.2

**URL:** https://discourse.vtk.org/t/a-multi-volume-problem-of-vtk9-2/9287
**Category:** VR/AR
**Created:** [September 6, 2022, 1:37pm UTC](https://discourse.vtk.org/t/a-multi-volume-problem-of-vtk9-2/9287 "2022-09-06T13:37:46Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![YRFPC03](https://discourse.vtk.org/user_avatar/discourse.vtk.org/yrfpc03/32/5739_2.png) [@YRFPC03](https://discourse.vtk.org/u/YRFPC03)
#### Post date: [September 6, 2022, 1:37pm UTC](https://discourse.vtk.org/t/a-multi-volume-problem-of-vtk9-2/9287/1 "2022-09-06T13:37:46Z")

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When I use multi volume to render multi-body data, the rendering result I get becomes very dim, which is not the case when I render single body data. I have used vtk9，i don’t change the ColorTransferFunction and else  
before

 ![头颅](https://discourse.vtk.org/uploads/default/original/2X/4/493908b139f807b45705fad21652d9d228e798f7.png)

 ![呼吸道](https://discourse.vtk.org/uploads/default/original/2X/7/72d9ffb858526282549b9286f57910573a633679.png)  
after  
 ![叠加效果](https://discourse.vtk.org/uploads/default/original/2X/8/813d3cd5342380ffb6afeacda383d3a11b1928e2.jpeg)

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<div class="post-metadata">

### Author: ![YRFPC03](https://discourse.vtk.org/user_avatar/discourse.vtk.org/yrfpc03/32/5739_2.png) [@YRFPC03](https://discourse.vtk.org/u/YRFPC03)
#### Post date: [September 6, 2022, 1:40pm UTC](https://discourse.vtk.org/t/a-multi-volume-problem-of-vtk9-2/9287/2 "2022-09-06T13:40:48Z")

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This is my code about the multi-volume  
vtkSmartPointer mapperOfbonds = vtkSmartPointer::New();  
mapperOfbonds-\>SetScalarModeToDefault();  
mapperOfbonds-\>SetSampleDistance(1.0);  
mapperOfbonds-\>SetInputConnection(0,readerOfVtk-\>GetOutputPort());  
mapperOfbonds-\>SetInputConnection(1, extractVOI-\>GetOutputPort());  
mapperOfbonds-\>Update();  
vtkSmartPointer testVolume = vtkSmartPointer::New();  
testVolume-\>SetMapper(mapperOfbonds);  
testVolume-\>SetVolume(volume1,0);  
testVolume-\>SetVolume(volume,1);  
testVolume-\>Update();