# How to mesh concentric irregular ellipsoid ?

**URL:** https://discourse.vtk.org/t/how-to-mesh-concentric-irregular-ellipsoid/6911
**Category:** Support
**Created:** [October 18, 2021, 3:23pm UTC](https://discourse.vtk.org/t/how-to-mesh-concentric-irregular-ellipsoid/6911 "2021-10-18T15:23:38Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![Texas](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Texas](https://discourse.vtk.org/u/Texas)
#### Post date: [October 18, 2021, 3:23pm UTC](https://discourse.vtk.org/t/how-to-mesh-concentric-irregular-ellipsoid/6911/1 "2021-10-18T15:23:38Z")

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Hello,

Me question is specific: as the title said, I am trying to mesh concentric ellipsoid. Each ellipsoid defined by cloud point. And I try to use de Delaunay\_2D method.

I use 2 consecutive ellipsoid and mesh it. I change the alpha depending on the maximum length between 2 consecutives point in each ellipsoid: [image\_1](https://ibb.co/YkN9RcN)

If I use an alpha that is less, I have  
The result is (more or less what I want): [image\_2](https://ibb.co/ygNvWj9)

If I adjust my beta to low, I have holes: [image\_3](https://ibb.co/WgVjKjP)

If I adjust my beta to high, I have so place were I have to much cells (ellipsoid alone and with the others: [image\_4](https://ibb.co/w7XC7D2) & [image\_5](https://ibb.co/6FGvdyg)

So, my idea is to use a beta too low and tri to fill the gap (since I have every point that I need) but if my holled\_surf

surf\_final = holled\_surf.delaunay\_2d(alpha=1)

it forgot completely the previous surface and mesh it as if my holled\_surf is only a cloud point and not an already meshed component.

So, does someone have any idea to solve my problem he or she is welcome ?  
(either by finishing my idea or having a completly new one)

(and since my coworker everytime tried it, no, there is no sweet beta where their is nor hole nor unwanted elements)

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### 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: [October 23, 2021, 9:10pm UTC](https://discourse.vtk.org/t/how-to-mesh-concentric-irregular-ellipsoid/6911/2 "2021-10-23T21:10:21Z")

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Hi,

Image 1 and Image 2 seem to be two successful examples. I guess I didn’t get the point.

regards,

Paulo

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### Author: ![Texas](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Texas](https://discourse.vtk.org/u/Texas)
#### Post date: [October 26, 2021, 12:33pm UTC](https://discourse.vtk.org/t/how-to-mesh-concentric-irregular-ellipsoid/6911/3 "2021-10-26T12:33:09Z")

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The image 1 is a “good example”  
the image 2 is almost good, but present some case of image 4 on it (but since it was good, i used it to show what i wanted, to try to discribe my pb in image 4 and 5.  
Finaly, I was able to solve my trouble :  
if an element have all 3 nodes on the same ellipsoïde, delete that element. And problem on image 4 and 5 are resolved thanks to that