# example's input data not found.
**URL:** https://discourse.vtk.org/t/examples-input-data-not-found/6308
**Category:** Support
**Created:** [August 6, 2021, 8:34am UTC](https://discourse.vtk.org/t/examples-input-data-not-found/6308 "2021-08-06T08:34:16Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@eton](https://discourse.vtk.org/u/eton)
#### Post date: [August 6, 2021, 8:34am UTC](https://discourse.vtk.org/t/examples-input-data-not-found/6308/1 "2021-08-06T08:34:16Z")
Hi, everyone.
when I try to run exampe “./Examples/GUI/Qt/FourPaneViewer” failed
I know I need a dicom file , but I can not find a dcm file in the src-dir, will anyone give me a suggestion? thanks.
```auto
2021-08-06 16:24:33.274 ( 0.329s) [6C6AF7C0]vtkDICOMImageReader.cxx:144 ERR| vtkDICOMImageReader (0x55687f39de10): Couldn't open /home/eton/opt/vtks/vtk-src/build/ExternalData/GUISupport/QtQuick/Testing/Data/Baseline/TestQQuickVTKRenderWindow.png
2021-08-06 16:24:33.274 ( 0.329s) [6C6AF7C0]vtkDICOMImageReader.cxx:237 ERR| vtkDICOMImageReader (0x55687f39de10): Either a filename was not specified or the specified directory does not contain any DICOM images.
2021-08-06 16:24:33.274 ( 0.329s) [6C6AF7C0] vtkExecutive.cxx:752 ERR| vtkCompositeDataPipeline (0x55687f259200): Algorithm vtkDICOMImageReader(0x55687f39de10) returned failure for request: vtkInformation (0x55687f493eb0)
Debug: Off
Modified Time: 4334
Reference Count: 1
Registered Events: (none)
Request: REQUEST_DATA
FROM_OUTPUT_PORT: 0
ALGORITHM_AFTER_FORWARD: 1
FORWARD_DIRECTION: 0
```
---
### Author:  [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [August 6, 2021, 1:13pm UTC](https://discourse.vtk.org/t/examples-input-data-not-found/6308/2 "2021-08-06T13:13:45Z")
You probably need to build the `ExternalData` target for VTK (called `VTKData`) to get it.
---
### Author:  [@eton](https://discourse.vtk.org/u/eton)
#### Post date: [August 6, 2021, 1:24pm UTC](https://discourse.vtk.org/t/examples-input-data-not-found/6308/3 "2021-08-06T13:24:08Z")
> [@ben.boeckel](#):
>
> `ExternalData`
so sorry about I am know too little about it. what you try to tell me is use another build command to build? because in my build directory already had a lot data in ./build/ExternalData also has some dicom file but when I use the dicom directory as parameter to it. it tell me not the right dicom file.
---
### Author:  [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [August 6, 2021, 1:41pm UTC](https://discourse.vtk.org/t/examples-input-data-not-found/6308/4 "2021-08-06T13:41:13Z")
Yes, it is `make VTKData`.
---
### Author:  [@eton](https://discourse.vtk.org/u/eton)
#### Post date: [August 9, 2021, 1:18am UTC](https://discourse.vtk.org/t/examples-input-data-not-found/6308/5 "2021-08-09T01:18:11Z")
> [@ben.boeckel](#):
>
> `make VTKData`
@ben.boeckel sorry to disturb again. but after a run the command, there’s no expected file generated. the dcm file I find already in there.
Below is the log info.
```auto
eton@9u:~/opt/vtks/vtk-src/build$ make VTKData
[100%] Built target VTKData
eton@9u:~/opt/vtks/vtk-src/build$ find ./ -name "*.dcm"
./ExternalData/Testing/Data/dicom/collection/IM-0001-1992.dcm
./ExternalData/Testing/Data/dicom/collection/IM-0001-1986.dcm
./ExternalData/Testing/Data/dicom/collection/IM-0001-1990.dcm
./ExternalData/Testing/Data/dicom/collection/IM-0001-1983.dcm
./ExternalData/Testing/Data/dicom/collection/IM-0001-1991.dcm
./ExternalData/Testing/Data/dicom/collection/IM-0001-1985.dcm
./ExternalData/Testing/Data/dicom/collection/IM-0001-1987.dcm
./ExternalData/Testing/Data/dicom/collection/IM-0001-1988.dcm
./ExternalData/Testing/Data/dicom/collection/IM-0001-1993.dcm
./ExternalData/Testing/Data/dicom/collection/IM-0001-1989.dcm
./ExternalData/Testing/Data/dicom/collection/IM-0001-1984.dcm
```
---
### Author:  [@eton](https://discourse.vtk.org/u/eton)
#### Post date: [August 9, 2021, 2:13am UTC](https://discourse.vtk.org/t/examples-input-data-not-found/6308/6 "2021-08-09T02:13:35Z")
Hi, everyone, based on the talk above, I think May be what I need most is a reference, but do not found it.
Are there any reference documents on examples and usage data? I didn’t find a valid reference in VTK examples.
---
### Author:  [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [August 9, 2021, 11:34am UTC](https://discourse.vtk.org/t/examples-input-data-not-found/6308/7 "2021-08-09T11:34:32Z")
How are you running the example?
---
### Author:  [@eton](https://discourse.vtk.org/u/eton)
#### Post date: [August 9, 2021, 12:37pm UTC](https://discourse.vtk.org/t/examples-input-data-not-found/6308/8 "2021-08-09T12:37:48Z")
the cli I use is:
```auto
~/opt/vtks/vtk-src/Examples/GUI/Qt/build-FourPaneViewer-Desktop_Qt_5_15_2_GCC_64bit-Debug/QtVTKRenderWindows ~/opt/vtks/vtk-src/build/ExternalData/Testing/Data/dicom/collection/
```
---
### Author:  [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [August 9, 2021, 1:21pm UTC](https://discourse.vtk.org/t/examples-input-data-not-found/6308/9 "2021-08-09T13:21:52Z")
Hmm. I don’t know. That _looks_ right to me, but maybe something is up with the reader not finding the files for some reason?
---
### Author:  [@eton](https://discourse.vtk.org/u/eton)
#### Post date: [August 9, 2021, 2:28pm UTC](https://discourse.vtk.org/t/examples-input-data-not-found/6308/10 "2021-08-09T14:28:42Z")
@ben.boeckel will you please take a screenshot about the program running result. and the ls result about
./ExternalData/Testing/Data/dicom/collection/
based on what you have and I will know what the example should be;
Because you take out the running results of your program, I can take your results as a basic standard, so that I can further judge where I should continue to deal with it.