Grid Creator for Surfer extends the 3D rendering capabilities of Surfer 8, by allowing you to export regular drawings to Surfer grid files. Your drawing grids can then be loaded as any of Surfer’s grid-based map types (image, wireframe, contour, shaded-relief, or surface). These drawing grids can also be “georeferenced” to your other data grids, allowing for creative overlays.
In addition to these capabilities, Grid Creator offers a utility to blank edge rows or columns, or specify a specific z value to blank. Using this feature, specific colors can be blanked, so they do not draw on your 3D surface maps.
Have a look at the help file for an example.