The RefreshShade command clears and regenerates the render mesh from selected objects so the shading refreshes.
In Rhino 4 and earlier, editing surface control points would not cause the render meshes to update. The RefreshShade command can be used to update the render meshes. It is a rarely used command in Rhino 5 and later.
Rhinoceros 6 © 2010-2019 Robert McNeel & Associates. 21-Aug-2019