# Spherical coordinates and filters

**URL:** https://discourse.paraview.org/t/spherical-coordinates-and-filters/8682
**Category:** ParaView Support
**Created:** [December 22, 2021, 6:45pm UTC](https://discourse.paraview.org/t/spherical-coordinates-and-filters/8682 "2021-12-22T18:45:58Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![pln](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/p/838e76/32.png) [@pln](https://discourse.paraview.org/u/pln)
#### Post date: [December 22, 2021, 6:45pm UTC](https://discourse.paraview.org/t/spherical-coordinates-and-filters/8682/1 "2021-12-22T18:45:58Z")

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Hello,

I am trying to extract a spherical surface from a dataset using paraview 5.8.1 spherical filters. I’m running into a problem that my spherical filter center at (0,0,0) doesn’t extend to the right radius. If I set radius to 1 it does not intersect the point at (1,0,0) but instead intersects at some point below.

I can duplicate this problem using spherical sources where I create one source centered at (0,0,0) with a radius of 1 and another at (1,0,0) with a small radius. The larger one does not intersect the center of the smaller one.

 ![Sphere](https://discourse.paraview.org/uploads/default/original/2X/5/5caba7cd79255e2c5a1ae165d4d38f872a910b23.png)

I am confused exactly what is going on and what I can do to get the correct center/radius for my fitler.

Thanks,  
Peter

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### Author: ![pln](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/p/838e76/32.png) [@pln](https://discourse.paraview.org/u/pln)
#### Post date: [December 22, 2021, 8:56pm UTC](https://discourse.paraview.org/t/spherical-coordinates-and-filters/8682/2 "2021-12-22T20:56:32Z")

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I found the issue but I’m not sure how to fix it or why this is the case. I looked into the information section for the sphere with radius 1 centered at (0,0,0) and the bounds are:

X Range: -0.97491 to 0.974928 (delta: 1.94984)  
Y Range: -0.97491 to 0.974928 (delta: 1.94984)  
Z Range: -1 to 1 (delta: 2)

So for some reason the sphere source isn’t producing a true sphere. Maybe I need to increase the resolution of it somehow? Changing the theta resolution parameter does not fix the issue.

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### Author: ![pln](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/p/838e76/32.png) [@pln](https://discourse.paraview.org/u/pln)
#### Post date: [December 22, 2021, 8:58pm UTC](https://discourse.paraview.org/t/spherical-coordinates-and-filters/8682/3 "2021-12-22T20:58:36Z")

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Found the solution. I have to increase the Phi resolution. Hopefully this can help someone else who is new.