Thank you for the answer.
My problem is a little bit more basic.
After the planar grid generation I have to assign to the grid nodes elevation data.
I could export the x-y grid coordinates to a gis software and there interpolate bathymetry data to the grid nodes. My question was, if there is a better and easier way in BlueKenue or also in Matisse without this exporting and importing operation. Further the grid nodes at my model boundaries should have the same elevation data as the polylines, with which I defined the model boundaries.
Regards,
Clemens