# Meshing complex shell models

**URL:** <https://prepomax.discourse.group/t/meshing-complex-shell-models/1750>\
**Category:** General Questions\
**Tags:** results\
**Created:** [May 15, 2024, 8:43am UTC](https://prepomax.discourse.group/t/meshing-complex-shell-models/1750 "2024-05-15T08:43:37Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [May 15, 2024, 8:54am UTC](https://prepomax.discourse.group/t/meshing-complex-shell-models/1750/2 "2024-05-15T08:54:49Z")

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Have you seen this recent thread ? [Difficulty in establishing a connection between 2 surfaces (shell) in Prepomax](https://prepomax.discourse.group/t/difficulty-in-establishing-a-connection-between-2-surfaces-shell-in-prepomax/1742)

> [@aleksa](#):
>
> Tied or tied constrained parts don’t work since the mesh nodes do not match between parts.

Meshes don’t have to match for these constraints to work. They have a tolerance that you can change to make them identify nodes further away than the default value allows. Of course, it should still be a reasonable distance and it’s important to select master and slave surfaces properly (master should have a coarser mesh).

> [@aleksa](#):
>
> Is there a way to identify the nodes that have opposite normals defined? The model has more than 300k nodes, using query tool is impractical.

In the Geometry tab, you can select Geometry → CAD Part → Flip Face Normal. It will display the face normals using 2 colors. but not per node (this is before meshing, just to check the geometry). To do it on the mesh, you could use ParaView.

> [@aleksa](#):
>
> How can I mesh this model correctly to avoid opposite normals error, if my normals are set correctly in the first place?

Maybe try meshing with the default mesher instead of Gmsh (add only the Meshing parameters object). If it doesn’t help, try using tie constraints instead of a single large compound.

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