Multiregion mesh
 

Hello,

What I should do to combine two different meshes (tetra, trimmer) on two regions (interfaces between regions were created)? Look at this catastrophe

thanks for any help

I'd mesh both regions poly. If you use the same mesh continuum for both regions and create the interface before meshing you get conformal mesh.
Also works with tets, but tets have only disadvantages compared to poly.