FlexPDE supports the ability to place mesh nodes at specific points in the problem geometry. This is done with the statements
NODE POINT (x_value , y_value)
NODE POINT (x_value , y_value , z_value)
A mesh node will be placed at the specified location, and linked into the computation mesh.
In moving mesh problems, NODE POINTS will move with the mesh; they will not be locked to the specified location unless appropriate POINT VALUE boundary conditions are used to freeze the point.
In 3D geometries, specification of only two coordinates will cause a vertical meshing line to be placed throughout the Z-coordinate range of the domain. A three-coordinate point will specify a single node. Placing NODE POINTS in coincidence with EXTRUSION surfaces will have undefined effects, and may lead to mesh generation failure.
An alternative way of forcing nodes is to run a FEATURE or REGION boundary to and through the desired point.