[lpelizzari]

I have a wing surface that's intersecting with my symmetry surface, like this:
.

I tried cutting it off by creating a curve where the wing surface and the symmetry surface meet; dividing the wing surface by cutting it with this curve; and then deleting it.

But I can't do this!! What else can I do?

[Gert-Jan]

If you cannot split the surface, then don't worry, you can create a mesh by doing the following, provided you create a regular tet-prisms-mesh (Robust), and not a hexmesh:

1. leave the wing and symmetry surfaces as they are (focus only on curves and points).
2. remove the curve as attached to the wing surface above the symmetry plane, i.e. outside your volume.
3. create a new curve on the intersection of the wing surface and the symmetry plane. There is a button for this.
4. Create points at the ends of this new curve. There is also a button for this.
5. Create your Tet-mesh.

If done correctly, no elements will be present on the part of the surface that is outside the smmetry plane.

The reason this works is that ICEM
- first creates a mesh in and around the geometry
- seconcdly projects the nodes on the geometry
- then deletes elements that are outside the volume of your geometry.

The magic is the hierarchy in projection in the second step. ICEM first projects nodes on points, then on curves and then on surfaces. So ICEM will first nicely project nodes on the points and the curves that you created. Then it will project elements on the wing surface on both sides of the symmetry surface. However, the elements on the wing outside the symmetry plane are outside your volume, so these will be deleted. As a result, a flat mesh will remain on your symmetry plane. It is smooth because of the preferred projection of the nodes on the curve & points that you created on the intersection.