Hi Stanislaw, All lines and surfaces in the gmsh script have been defined as transfinite, in order to force a structured mesh generation, and I have verified that all elements are quads. Best regards,Oliviu On Wednesday, October 17, 2018, 8:38:33 PM GMT+1, Stanisław Gepner <sgepner@meil.pw.edu.pl> wrote: Hi, a wild guess would be that you have a mix of triangles and quads in a composite. From what I remember this is not supported. Pozdrawiam, Stanisław Gepner Dnia 17 października 2018 21:32:19 CEST, Oliviu Sugar <oliviu_sugar@yahoo.com> napisał(a): Dear all, I've run into some problems when trying to convert a msh file (generated using gmsh 4.0.2) into a xml file, using NekMesh.The script geo file used with gmsh is attached.The error encountered by NekMesh is: "Different types of elements in same composite!" Any advice on what needs to be changed in the geo file to resolve this issue would be much appreciated. Best regards,Oliviu