# Problem running SimpleRayCast.py example
**URL:** https://discourse.vtk.org/t/problem-running-simpleraycast-py-example/8092
**Category:** Support
**Created:** [March 20, 2022, 5:59pm UTC](https://discourse.vtk.org/t/problem-running-simpleraycast-py-example/8092 "2022-03-20T17:59:41Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Arni](https://discourse.vtk.org/u/Arni)
#### Post date: [March 20, 2022, 5:59pm UTC](https://discourse.vtk.org/t/problem-running-simpleraycast-py-example/8092/1 "2022-03-20T17:59:41Z")
Hello. I am trying to learn vtk but I am having problems running some of the examples. I tried some basic examples and they were working fine, but some examples that require a filename argument gave me problems. Specifically, the SimpleRayCast.py example gives me the following error when I run “vtkpython SimpleRayCast.py ironProt.vtk”
( 0.163s) [main thread] vtkDataReader.cxx:567 ERR| vtkStructuredPointsReader (0x55db3b5e5560): Unrecognized file type: version [Redirecting…](https://git-lfs.github.com/spec/v1) for file: ironProt.vtk
( 0.163s) [main thread] vtkDataReader.cxx:567 ERR| vtkStructuredPointsReader (0x55db3b5e5560): Unrecognized file type: version [Redirecting…](https://git-lfs.github.com/spec/v1) for file: ironProt.vtk
( 0.213s) [main thread]vtkFixedPointVolumeRayC:1122 ERR| vtkFixedPointVolumeRayCastMapper (0x7f7e1dc70010): Cell Scalars not supported
Loguru caught a signal: Loguru caught a signal: SIGSEGVSIGSEGV
Loguru caught a signal: SIGSEGV
Loguru caught a signal: SIGSEGV
Loguru caught a signal: SIGSEGV
Loguru caught a signal: SIGSEGV
Loguru caught a signal: Loguru caught a signal: SIGSEGVSIGSEGV
Stack trace:
4 0x7f7e27e77163 clone + 67
3 0x7f7e264ae609 /lib/x86\_64-linux-gnu/libpthread.so.0(+0x8609) [0x7f7e264ae609]
2 0x7f7e1f7acdac /home/vv/VTK-9.1.0/build/lib/python3.9/site-packages/vtkmodules/…/…/…/libvtkRenderingVolume-9.1.so.1(+0x2c9dac) [0x7f7e1f7acdac]
1 0x7f7e1f68d71d vtkFixedPointVolumeRayCastCompositeHelper::GenerateImage(int, int, vtkVolume\*, vtkFixedPointVolumeRayCastMapper\*) + 71
0 0x7f7e27d9b0c0 /lib/x86\_64-linux-gnu/libc.so.6(+0x430c0) [0x7f7e27d9b0c0]
( 0.223s) [1ABEC700] :0 FATL| Signal: SIGSEGV
Segmentation fault (core dumped)
I have only recently installed vtk on my ubuntu pc and I know very little. Any help to understand the problem would be much appreciated. Thank a lot!
---
### Author:  [@amaclean](https://discourse.vtk.org/u/amaclean)
#### Post date: [March 20, 2022, 10:06pm UTC](https://discourse.vtk.org/t/problem-running-simpleraycast-py-example/8092/2 "2022-03-20T22:06:06Z")
I suspect you need to download the data file not the git lfs link. Open the file you downloaded in a text editor and if it looks like this:
```auto
version https://git-lfs.github.com/spec/v1
oid sha256:544f67d66dbb8b79e48053f131d614e225d0caa702fd3f690313312dd4119f79
size 314642
```
then its the lfs-link not the actual file.
If this is the case, just check out the whole vtk-examples repository and the lfs links will be resolved.
---
### Author:  [@Arni](https://discourse.vtk.org/u/Arni)
#### Post date: [March 21, 2022, 8:19am UTC](https://discourse.vtk.org/t/problem-running-simpleraycast-py-example/8092/3 "2022-03-21T08:19:34Z")
Thanks a lot! That solved it. I wasn’t aware of git-lfs…