Thin Surfaces / internal Walls in SnappyHex - Problem with patch allocation
 

Hi,

sorry for reposting here, but I fear my question would get lost in the subforum otherwise.

I'm trying to generate a mesh around a thin surface / internal wall like a sail. Basically, it works fine, the STL surface mesh is found, properly resolved and written out as external faces / boundary patch. My problem is the following: I haven't managed to assign different boundary patch identifiers to the two sides of the surface, both sides are within one patch with associated normals pointing both directions. I cannot separate them by mergeOrSplitBaffles as the nodes of both sides are not identical. When importing two identical STL surfaces meshes with opposed normals, I get two patches, both seriously fragmented. I know that some have just assigned a finite thickness to their geometry when working on similar problems, others (Russo et al) have written additional routines to get around it. I'm trying to avoid both.

Does anybody know whether a) there is a way to either generate a volume mesh around an infinetly thin geometry with both sides in separate boundary patches or b) split the single boundary patch into two along the edges?

Cheers,
Hannes