TUFLOW Message 2400
WARNING 2400 - Hidden node not allocated as a primary node to a 2D2D link cell in 2D Domain XXXX. Review 2D2D link line shape and check vertex spacing is not too close.
At each vertice along the 2d_bc 2D link line (and any automatically inserted vertices using the d maximum distance attribute) a "hidden" 1D node is inserted. The 1D nodes act as storage that convey the water from one 2D domain to the other. Closely spaced 1D nodes can create several nodes with small storage and should be avoided.
Specify a 'd' value for the 2d_bc 2D link line of 2 to 3 times the larger 2D cell size. Alternatively, specify a 'd' value of 0 and control the number and location of nodes by inserting vertices on the line. The undocumented .tcf command Reveal 1D Nodes == ON can be used to provide additional information on the 'hidden' 1D nodes.
Occasionally this warning message has been found to occur at 2d_bc boundaries of type 'QT'. This is the result of the changes to the 2D-2D Approach that were introduced in Build 2013-12-AC. In this situation, the message has been outputted in error and is not of concern.