Hi, I have problems with merging two 2D meshes. I want to merge two meshes generated with genbox: 1. walls.box This mesh is an "Y"-type mesh. It goes from beeing a square of side 10 into a square of side 0.5 via two circles (of radii 1.1 and 1.0). 2. center.box This is an "Box"-type mesh. It is a square of size %%%%%%%%%%%%%%%%%%%%%%%% This is walls.box: reafile.rea 2 1 # Y 4 -8 0. 0. bbccb 0.5 0.6 1. 1.1 10. 0 1 1 W ,W ,E ,E , %%%%%%%%%%%%%%%%% And this is center.box: reafile.rea 2 1 # Box -2 -2 -0.5 0.5 1. -0.5 0.5 1. W ,W ,W ,W , %%%%%%% I can plot the two meshes on top of each other, and the elements seem to align perfectly. I use nekmerge2 (from the example case "expansion") to generate a merged .rea file: nekmerge2 center walls bottom I now obtain a bottom.rea file. I generate bottom.map using genmap (tolerance 0.2). I compile (using a bottom.usr file and a SIZE file) using makenek. I run serially using "nek". Now I get several warnings of the type: WARNING2 Element mesh mismatch at: I,J,K,IE: 1 2 1 1 Near Y = -0.50000000 -0.41269471 0.0000000 , d: 0.0000000 -0.36629354E-01 2.0000000 And then "Mesh consistency check failed. EXITING in VRDSMSH." No output is generated. What is the problem here? Have I missed some critical aspect of merging meshes? Best, Johan