# Does FreeFEM support meshes with hanging nodes?

**URL:** <https://community.freefem.org/t/does-freefem-support-meshes-with-hanging-nodes/363>\
**Category:** General Discussion\
**Created:** [April 21, 2020, 9:50pm UTC](https://community.freefem.org/t/does-freefem-support-meshes-with-hanging-nodes/363 "2020-04-21T21:50:55Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Pratikk17](https://avatars.discourse-cdn.com/v4/letter/p/e36b37/32.png) [@Pratikk17](https://community.freefem.org/u/Pratikk17)\
**Post date:** [April 21, 2020, 9:50pm UTC](https://community.freefem.org/t/does-freefem-support-meshes-with-hanging-nodes/363/1 "2020-04-21T21:50:55Z")

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Hi,

I have created a nonconforming mesh( with hanging node) in .msh format using Matlab. I need to solve the Laplace equation with homogeneous Dirichlet boundary conditions using CG/DG method. I can import this mesh into Freefem. I used the usual weak formulation of the Laplace equation, but Freefem does not compute the exact solution.

My question is, does FreeFEM++ solves any PDE on meshes with hanging nodes? If yes, how to treat these hanging nodes?

Thank you.  
Best regards,  
Pratik

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<div class="post-metadata">

**Author:** ![Pratikk17](https://avatars.discourse-cdn.com/v4/letter/p/e36b37/32.png) [@Pratikk17](https://community.freefem.org/u/Pratikk17)\
**Post date:** [April 21, 2020, 10:07pm UTC](https://community.freefem.org/t/does-freefem-support-meshes-with-hanging-nodes/363/2 "2020-04-21T22:07:52Z")

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![mesh](https://canada1.discourse-cdn.com/flex030/uploads/freefem/original/1X/7617215be6aa78e1cb986e2c69863d76070596d0.jpeg)

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**Author:** ![prj](https://avatars.discourse-cdn.com/v4/letter/p/ecae2f/32.png) [@prj](https://community.freefem.org/u/prj)\
**Post date:** [April 22, 2020, 5:11am UTC](https://community.freefem.org/t/does-freefem-support-meshes-with-hanging-nodes/363/3 "2020-04-22T05:11:34Z")

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No, FreeFEM does not support meshes with hanging nodes.

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**Author:** ![Carbaholic](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/carbaholic/32/158_2.png) [@Carbaholic](https://community.freefem.org/u/Carbaholic)\
**Post date:** [May 19, 2020, 5:40pm UTC](https://community.freefem.org/t/does-freefem-support-meshes-with-hanging-nodes/363/4 "2020-05-19T17:40:39Z")

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It wouldn’t be too hard to make your mesh valid though, all you would have to do is divide the larger rectangles into five elements instead of four.