GiD user manual : Correcting surfaces and creating a conformal mesh

  • With the option View->Zoom In , magnify the zone illustrated.

Zone in the mesh to zoom in.

  • Select View->Mode->Geometry to visualize the geometry of the piece.

The zone in geometry mode

There is a rectangular surface that does not fit within the boundaries of a rounded-corner surface (a hole, in this case). We will suppose that the problematic surface is planar. This way, it can be erased and recreated only with the information of its boundary in order to fit the rounded-corner boundary.

  • Select Geometry->Delete->Surfaces . Select the problematic surface, but before pressing ESC . Go to Contextual menu and select Lower Entities. With this option, the surface and lines and points that belongs to only this surface will be deleted.

Deleting surface and its lines and points

  • With Geometry->Create->NURBS surface->By contour create a new surface. Select the lines defining the contour and press ESC.

Result surface

  • Visualize the mesh again View->Mode->Mesh You will see that the mesh of the deleted surface is also deleted, but a new surface is created and it is not meshed. If you want to see the results of the first correction, the mesh must be regenerated with Mesh->Generate mesh . The problem has been fixed on this part. 

Note: only the mesh of the new surface will be really generated, the mesh of the rest of surfaces is cached to save resources

  • Use View->Higher entities->Edges on mesh mode, and magnify the next problematic zone (see image).
  • Second part to repair Select View->Mode->Geometry .

In this example, the situation involves a contour of four lines that does not correspond to any real surface (of the piece). These lines were too far apart to be collapsed.

  • Select Geometry->Create->NURBS surface->By contour . Select the lines. Press ESC twice.

Contour lines that define the surface

  • Visualize again higher entities View->Higher entities->Edges and magnify the next zone indicated.

Mesh around the problematic part

  • Select View->Mode->Geometry .

There are two surfaces that overlap each other at one end.
The magnified zone with two overlapping surfaces.

In this case the best solution for correcting the boundary is to trim the overlap.

  • Select Geometry->Create->NURBS surface->Trimmed .
  • Select the surface to be trimmed. Then select the new boundary.

The surface to be trimmed and the new boundary.

  • Select Geometry->Delete->Surfaces . Select the original surface. Press ESC twice.

The original surface to be deleted.

  • Use Geometry->Delete->Lines and select all visible lines, and after delete the points with Geometry->Delete->Points and select all visible points. Only the isolated lines and isolated points will be deleted (lines that belong to surfaces or points that belong to curves won't be delete, also if they were selected).


Lines and point that no longer belong to any surface and will be deleted.

  • Select Mesh->Generate mesh . Then visualize the result using the option View->Higher entities->Edges .

Higher entities of the result model

A conformal mesh has been achieved, all edges are interior, higher entities=2, except the ones on the boundary with higher entities=1.

There is a node that don't belong to any element, this is because an isolated point that don't belong to any line. This point can be deleted with  

Geometry->Delete->Points

and can select all the points, only the ones with higherenties=0 will be allowed to be deleted.