# Threshold on slice using an ellipse

**URL:** https://discourse.paraview.org/t/threshold-on-slice-using-an-ellipse/4532
**Category:** ParaView Support
**Created:** [June 7, 2020, 4:16pm UTC](https://discourse.paraview.org/t/threshold-on-slice-using-an-ellipse/4532 "2020-06-07T16:16:37Z")
**Posts on this page:** 1
**Showing post:** 3

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### Author: ![yek\_irani](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/y/f07891/32.png) [@yek\_irani](https://discourse.paraview.org/u/yek_irani)
#### Post date: [June 8, 2020, 6:33pm UTC](https://discourse.paraview.org/t/threshold-on-slice-using-an-ellipse/4532/3 "2020-06-08T18:33:03Z")

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Hello again,

Many thanks for your response. The clip filter with a sphere worked and it was very straightforward. I am having trouble with the Calculator filter. The equation for the ellipse which I am interested in, I entered as follows in the calculator: X^2/(13.8e-3)^2+Z^2/(9.1007e-3)^2=1. But, when I enter Apply, I get error messages which I have pasted below.

I then used:

coordsX^2/(13.8e-3)^2+coordsZ^2/(9.1007e-3)^2=1

That didn’t generate error messages. But the result does not look like anything I expected.  
I also found the following thread. I am not sure how relevant it is to the problem at hand: [slice along polyline](https://discourse.paraview.org/t/slice-along-polyline/1633)

Just to clarify: Am I supposed to do a clip at Y-normal, and then create the calculator with the elliptical equation, followed by the scalar clip?  
[sphere.tiff](https://discourse.paraview.org/uploads/short-url/m39kSlfa1eYjlJogRjCkCWChX8n.tiff) (2.6 MB)  
What I want to see is the elliptical equitvalent of the attached plot.

Thank you.  
Maziar.

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