*
* It is your duty to guarantee that cells have the correct orientation.
* To guarantee this, in the input vector keeping the cell list, the
- * vertex indices for each cell have to be in a defined order. In one
- * dimension, the first vertex index must refer to that vertex with the
- * lower coordinate value. In two dimensions, the four vertices must be
- * given in an order representing a counterclockwise sense. This
- * condition is not easy to verify and no full attempt to do so is made.
+ * vertex indices for each cell have to be in a defined order, see the
+ * documentation of GeometryInfo<dim>. In one dimension, the first vertex
+ * index must refer to that vertex with the lower coordinate value. In 2d
+ * and 3D, the correspondoing conditions are not easy to verify and no
+ * full attempt to do so is made.
* If you violate this condition, you may end up with matrix entries
* having the wrong sign (clockwise vertex numbering, which results in
* a negative area element) of with wrong matrix elements (twisted