system error

Hi All
I used dream3D generated a microstructure. When I try to use Netgen mesh the stl file. If the microstructure only contain 1 single grain (1 stl file), it work. If it has multiple grain (more than 1 stl files), it show a system error: get neighbourpoints failed . Does any one know how to solve this?

Thank you for helping

The stl mesher does only support one domain (since in stl files there is no way afaik to specify multiple domains, it contains just the triangulation.
If the meshes do not overlap you can mesh the surfaces seperately and then merge the meshes, there is a tutorial here:

I tried to mesh each stl file and merge them together. When I load the geometry of a single stl file (eg. I attached one), it show an error: ## (eg. 6184) wrong oriented neighbourtrangles found. It still show the same system error when I mesh this single stl file. Do you know what is the issue in here?

Thank you for answering my question

Attachment: GrainFeature_2.stl