If you want to limit a 3D surface to a smaller range of z values than is currently shown, you can use Grids | Calculate | Math to assign NoData values to the areas above and below certain Z values. For example, if you want to limit the surface map to show only areas with a Z value between 40 and 80, you can:
- Click Grids | Calculate | Math.
- In the Grid Math dialog, click the Add Grids button.
- Select your grid file and click Open.
- In the Grid Math dialog, enter the following function into the Enter a function... box: If (A>40 and A<80, A, 1.70141e+38). This tells Surfer that if a Z value in grid A is between 40 and 80, then use that Z value in the output grid, otherwise use the NoData value.
- Click OK and the new grid is created.
- Create a new map from this new grid or replace the grid for the existing 3D Surface layer with this new grid.
If you would like a way to set the z axis limits for a 3D map without having to modify the grid, you can email firstname.lastname@example.org to add your vote to this request on the suggestion file.
Updated October 31, 2018