Hi, if you want to create a periodic mesh based on one shape, please find therefore the attached example . This feature is often used when propeller have to be exported to stl files for a viscous calculation. The procedure is as follows: 1. create all need surfaces 2. for surface visualization put all surfaces into a ImageSurfaceGroup and use this as source of the PeriodicImages feature. This feature can be found in the transformation tap. 3. create a TriMesh with all needed surfaces 4. Use this TriMesh as a source for the feature definition periodicmesh best regards Carsten periodic.fdb