# Remove background displacement
**URL:** https://discourse.paraview.org/t/remove-background-displacement/16489
**Category:** ParaView Support
**Created:** [April 16, 2025, 3:16pm UTC](https://discourse.paraview.org/t/remove-background-displacement/16489 "2025-04-16T15:16:10Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Federico\_Feliziani](https://discourse.paraview.org/u/Federico_Feliziani)
#### Post date: [April 16, 2025, 3:16pm UTC](https://discourse.paraview.org/t/remove-background-displacement/16489/1 "2025-04-16T15:16:10Z")
I’ve run a numerical simulation to model the impact of a wave on a cliff, and I’m currently post-processing the results in ParaView. Before the wave impact (which occurs at time step 18), the model records some background displacements. What I’d like to do is clean up the visualization so that it only shows the displacement caused by the wave impact, excluding the background displacement. What’s the best way to achieve this in ParaView?
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [April 16, 2025, 3:23pm UTC](https://discourse.paraview.org/t/remove-background-displacement/16489/2 "2025-04-16T15:23:56Z")
Please share a screenshot highligting the issue
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### Author:  [@Federico\_Feliziani](https://discourse.paraview.org/u/Federico_Feliziani)
#### Post date: [April 16, 2025, 3:35pm UTC](https://discourse.paraview.org/t/remove-background-displacement/16489/3 "2025-04-16T15:35:30Z")
I appreciate your response, Mathieu.
All of the frames that I exported from Paraview are available here:
> **[forum.rar](https://wetransfer.com/downloads/34599a61a5fefd41c7deee173887f75e20250416153115/1ba9a1?t_exp=1745076675&t_lsid=19fb5578-f748-4ae6-b716-d3a1952e975a&t_network=link&t_rid=ZW1haWx8YWRyb2l0fDA5ZDcyYjYyLWIwMDAtNDZmZS1hZTYwLTUxMmE1YTgzMDJkNQ==&t_s=download_link&t_ts=1744817490)**
>
> 1 file sent via WeTransfer, the simplest way to send your files around the world
Starting at time step 18, pressure is applied to the model’s right face. Even though there are some background displacements prior to that time step, it is difficult to visualize the induce displacement. Filtering the entire simulation from the initial noise displacement at time step 18 will allow me to see only the induced displacements.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [April 16, 2025, 3:50pm UTC](https://discourse.paraview.org/t/remove-background-displacement/16489/4 "2025-04-16T15:50:16Z")
For reference:
You could recover the data at frame 18 and substract that but since what you are looking for is tiny compared to the more broad changes, it may not be exactly what you are looking for.
Anyway, to do that using ForceTime and PythonCalculator with multiple inputs to compute the difference.
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### Author:  [@Federico\_Feliziani](https://discourse.paraview.org/u/Federico_Feliziani)
#### Post date: [April 16, 2025, 3:54pm UTC](https://discourse.paraview.org/t/remove-background-displacement/16489/5 "2025-04-16T15:54:49Z")
Thank you Mathieu!
Can you suggest some references for me to follow?
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [April 16, 2025, 3:57pm UTC](https://discourse.paraview.org/t/remove-background-displacement/16489/6 "2025-04-16T15:57:39Z")
- Add a ForceTime filter, select frame 18, Apply
- Select both your data and forcetime using control key
- Add a python calculator
- Use expression `inputs[0].PointData["displacement"] - inputs[1].PointData["displacement"]`
- Apply