This is a pure bug fix and not a feature extension. It might affect your snappyHexMesh meshes. In v1712 and earlier the featureAngle setting in the layer controls section of the snappyHexMeshDict
// When not to extrude surface. 0 is flat surface,
// 90 is when two faces are perpendicular. Note that this
// is the angle of the mesh surface (so after snapping) and not
// the original geometry.
was not interpreted correctly (it was missing a degrees-to-radians conversion). Consequently in v1712 any setting greater than 60 degrees would disable all layer extrusion.
In below figures the effect (in v1806) of two feature angles is shown:
- 45 degrees i.e. disabling all extrusion in sharp angles
- 130 degrees, i.e. allowing extrusion in sharp angles)
Note: some default values of parameters are calculated from above featureAngle setting. These parameters are:
// Do not extrude around sharp edge if not both faces are extruded.
// Default is 0.5*featureAngle. Set to -180 always attempt extrusion
// Optional: at non-patched sides allow mesh to slip if extrusion
// direction makes angle larger than slipFeatureAngle. Default is
Hence if you change the featureAngle parameter in v1806 and would like to get exactly the same behaviour as v1712 you need to adjust these settings correspondingly. Expressed as a conversion table:
|featureAngle v1712||featureAngle v1806||mergePatchFaces||layerTermination||slipFeature|