# Remeshing of deformed meshes

**URL:** https://community.geodynamics.org/t/remeshing-of-deformed-meshes/793
**Category:** ASPECT
**Created:** [September 9, 2019, 12:26pm UTC](https://community.geodynamics.org/t/remeshing-of-deformed-meshes/793 "2019-09-09T12:26:26Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![anne-glerum](https://yyz2.discourse-cdn.com/flex036/user_avatar/community.geodynamics.org/anne-glerum/32/283_2.png) [@anne-glerum](https://community.geodynamics.org/u/anne-glerum)
#### Post date: [September 9, 2019, 12:26pm UTC](https://community.geodynamics.org/t/remeshing-of-deformed-meshes/793/1 "2019-09-09T12:26:27Z")

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Lithospheric deformation models can lead to highly distorted meshes. As pointed out by Wolfgang in Issue #526,

> you will eventually come to a point where the cells at the shear band will just be too deformed and there is nothing you can do other than doing a complete remeshing – which the current code cannot do, and I cannot really see how we would support it either.

What are the obstacles for supporting remeshing?

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### Author: ![bangerth](https://yyz2.discourse-cdn.com/flex036/user_avatar/community.geodynamics.org/bangerth/32/52_2.png) [@bangerth](https://community.geodynamics.org/u/bangerth)
#### Post date: [September 10, 2019, 12:34am UTC](https://community.geodynamics.org/t/remeshing-of-deformed-meshes/793/2 "2019-09-10T00:34:44Z")

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Anne,  
you have to move nodes as a first step in a way that improves the mesh  
quality. That is a relatively simple step that could without much  
difficulty be implemented in ASPECT. In fact, it’s a process not  
terribly different from the way the free surface implementation  
reassigns points in the interior.

The more difficult step is that you somehow need to interpolate data  
from the old to the new mesh. This implies that you will have to find  
where each new node point was located on the old mesh – a very  
difficult and expensive step, in particular in parallel. I can imagine  
that one could approximate that in a similar way again as is done in the  
free surface implementation, where one just takes node values along with  
the node locations and then pretends in the next time step that there  
was a modified velocity field in action that undoes the accidental moves  
of data with nodes. This is something that can be done with good  
efficiency in parallel, whereas the interpolation process is something  
that I would try to avoid at all costs.

Best  
W.

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### Author: ![anne-glerum](https://yyz2.discourse-cdn.com/flex036/user_avatar/community.geodynamics.org/anne-glerum/32/283_2.png) [@anne-glerum](https://community.geodynamics.org/u/anne-glerum)
#### Post date: [September 24, 2019, 2:41pm UTC](https://community.geodynamics.org/t/remeshing-of-deformed-meshes/793/3 "2019-09-24T14:41:09Z")

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Hi Wolfgang,

1. Move mesh nodes to improve mesh.  
Currently the mesh deformation implementation reassigns points in the interior by solving the Laplace equation for mesh velocity. Multiplied by the timestep this gives the mesh displacements used in the mapping. Could we add a step that 1) checks the quality of the mesh (skewness, aspect ratio), then if needed, 2) applies some smoothing to the mesh, e.g. some form of Laplacian smoothing. The displacements computed in the smoothing step could then be added to the already computed displacements.

2. Interpolate data onto new mesh.  
Is this step taken care of when we add to the mesh displacements used in the mapping?

Thanks a lot,  
Anne
