* @param lowCellId index of the children cell to add (dimension n-1)
* @param aType vtk cell type of the cell to add (needed to find the SMDS_Downward structure containing the cell to add).
*/
* @param lowCellId index of the children cell to add (dimension n-1)
* @param aType vtk cell type of the cell to add (needed to find the SMDS_Downward structure containing the cell to add).
*/