# How to interpret VTK runtime error messages?

**URL:** https://discourse.vtk.org/t/how-to-interpret-vtk-runtime-error-messages/12139
**Category:** Support
**Created:** [August 11, 2023, 10:46pm UTC](https://discourse.vtk.org/t/how-to-interpret-vtk-runtime-error-messages/12139 "2023-08-11T22:46:39Z")
**Posts on this page:** 3
**Page:** 1

<div class="post-metadata">

### Author: ![Tomasso](https://discourse.vtk.org/user_avatar/discourse.vtk.org/tomasso/32/5786_2.png) [@Tomasso](https://discourse.vtk.org/u/Tomasso)
#### Post date: [August 11, 2023, 10:46pm UTC](https://discourse.vtk.org/t/how-to-interpret-vtk-runtime-error-messages/12139/1 "2023-08-11T22:46:39Z")

</div>

My VTK 9.2 C++ application generates multiple VTK error messages at runtime on stderr when building the pipeline, like this one:

> 2023-08-11 15:09:34.058 ( 0.335s) [443E680] vtkExecutive.cxx:740 ERR| vtkCompositeDataPipeline (0x563dd90c7d60): Algorithm vtkElevationFilter (0x563dd90c8a10) returned failure for request: vtkInformation (0x563dd90b1bb0)  
> Debug: Off  
> Modified Time: 36  
> Reference Count: 1  
> Registered Events: (none)  
> Request: REQUEST\_DATA\_OBJECT  
> ALGORITHM\_AFTER\_FORWARD: 1  
> FORWARD\_DIRECTION: 0

How to interpret this message? My VTK pipeline includes a vtkElevationFilter.

---

<div class="post-metadata">

### Author: ![Paulo\_Carvalho](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulo_carvalho/32/370_2.png) [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)
#### Post date: [August 12, 2023, 9:59pm UTC](https://discourse.vtk.org/t/how-to-interpret-vtk-runtime-error-messages/12139/2 "2023-08-12T21:59:50Z")

</div>

Hello,

Diagnosing the problem based on those messages alone is a bit difficult indeed. Those messages are not very clear. Try simplifying or commenting out portions of the pipeline to the point the error ceases, then add one part, check, add one part, check… At one point you’ll get the error message. This may help pinpointing the issue.

take care,

PC

---

<div class="post-metadata">

### Author: ![mwestphal](https://discourse.vtk.org/user_avatar/discourse.vtk.org/mwestphal/32/19_2.png) [@mwestphal](https://discourse.vtk.org/u/mwestphal)
#### Post date: [August 16, 2023, 2:26pm UTC](https://discourse.vtk.org/t/how-to-interpret-vtk-runtime-error-messages/12139/3 "2023-08-16T14:26:05Z")

</div>

> [@Tomasso](#):
>
> vtkElevationFilter

> Request: REQUEST\_DATA\_OBJECT

this means that vtkElevationFilter fail to perform its RequestDataObject method. However, figuring out why is the tricky part, especially since vtkElevationFilter should not even need to create any king of data object.

To figure it out, you need to start debugging.